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Subseries 1. Samuel Pierpont Langley, 1884-1889

Scope and Content Notes:

Samuel Pierpont Langley was the first Director of the Allegheny Observatory and held that position from 1867 to 1887. His primary interest was the sun and he began his studies of the sun immediately after assuming the post of Director. Langley prepared drawings of sun spots and associated phenomena and astronomers, today, are still familiar with Langley's classic drawing of the great sunspot of 1873.

In 1869 Langley devised and made operational the electric system of transmitting telegraphic time to several of the Pennsylvania Railroad lines which were associated with the observatory. In the area of magnetic disturbances, Langley was the first to associate such disturbances on the earth with solar outbreaks of an extremely active character.

Concerning studies in the realm of solar physics, Professor Langley was impressed with the idea that much radiant energy from the sun could not be recognized with instruments then in use, and after much experimentation, he invented the bolometer. With this instrument he succeeded in measuring the amount of heat radiation on the earth from the sun (the solar constant).

Professor Langley studied many minor though important questions concerning radiant energy. His investigations of the moon's temperature added greatly to our knowledge of the moon. Langley used his spectrobolometer to measure the highest temperature of the moon which was found to be approximately zero degrees centigrade and the lowest temperature of the moon which was found to be equivalent to the temperature of space.

Langley also collected data on the part of the solar system beyond the infra-red zone. With the aid of Professors Keeler, Very, and Page measurements were made by Langley utilizing the spectrobolometer and the galvanometer which he invented before photographic methods were develop.

Langley, of course, has received much recognition for his contributions to aeronautics. However, his original intention was not to construct a flying-machine, but instead to "determine the laws governing flight." At the Allegheny Observatory, Langley built a whirling arm on which "he tested airfoils, fusiforms and other aerodynamic objects, measuring their angels and pressures as they moved through the air at varying speeds." Studies of actual birds and "mechanical birds" ("winged contrivance" made of tin, cork, and rubber) were conducted and findings published in a paper entitled "Experiments in Aerodynamics."

Professor Langley left his post at the Allegheny Observatory in 1887 (leaving F.W. Very, his assistant, in charge) to become Assistant Secretary of the Smithsonian Institution; later, following the death of Professor Baird, he was elected Secretary of the Institution in 1891. Langley continued his research in aerodynamics and from a catapult, on May 6, 1896, launched an unmanned, steam-powered flying machine over the Potomac. It flew more than a half mile and was subsequently recovered. The first manned flight of his gasoline-powered "aerodome" failed in 1903 because of a launching device defect. Glenn Curtiss successfully piloted Langley's restored plane eight years after his death.

Note: Calendar entries covering the period 1884-1889 (Letterpress books no.'s I, II, and III) consist of abstracts of letters selected from four areas of research: 1) magnetic disturbances, 2) solar radiation, 3) mapping of infra-red spectrum, and 4) aerodynamics. There are also selected abstracts relating to both the electric time signal service and miscellaneous correspondence.

Please note that references to pagination indicate number of pages letters occupy in letterpress books and not necessarily number of pages of actual letters.


Box 30
Volume 1 Samuel Langley, 1862-1872
Volume 2 Samuel Langley, 1884-1887

This calendar, comprised of Volumes 2-3, was prepared by David Lieberman, a student in the Graduate School of Library and Information Sciences, University of Pittsburgh, as an independent study project during September - December, 1973.

1. Reed, J.R. Pittsburgh, PA Comparative bolometer measurement to determine bolometer efficiency, 2p., March 6, 1884
2. Brashear, J.A. Allegheny, PA. Has examined Brashear's lens specimens and has enclosed several items including a bolometer carriage in order that Brashear might measure from it to prepare his own, 2p., March 7, 1884
3. Grunow, William. West Point, NY. Langley waiting with great interest the result of experiment with a 1/20 mm. single strip bolometer. [Page 2 of letter not legible, Ed.], 2p., March 7, 1884
4. Grunow, William. West Point, NY. A firm in Paris wishes to secure bolometers for the purpose, Langley supposes, of constructing others, 1p., March 8, 1884
5. Thaw, William. Allegheny, PA. A discussion of the conditions which cause a rise in the surface temperature of the Earth, 1p., March 14, 1884
6. Grunow, William. Encloses a draft for $100 for payment of construction of four bolometers, 2p., March 18, 1884
7. Grunow, William. West Point, NY. Langley needs badly a 1 mm. bolometer made of 1/10 mm. strips, 2p., March 18, 1884
8. Hazen, W.B. Washington, DC. Investigations on heat radiated from the earth's surface, 4p., March 18, 1884
9. Brashear, J.A. Allegheny, PA. [Page one not legible thus difficult to determine precise nature of correspondence. It appears that Langley has constructed a "Hot Box", Ed.], 6p., March 26, 1884
10. Hazen, W.B. Washington, DC. Observation of a "remarkable sunspot" seen on November 16, 1882, 1p., March 26, 1884
11. Comu, A. Concerning a new method for distinguishing between helluric and solar absorption, 2p., April 11, 1884
12. Fritts, E.E. New York, NY. Requests a sheet of selenium for experimental purposes, 2p., April 20, 1884
13. Grunow, William. West Point, NY. Acknowledge receipt of 0.1 mm. strip bolometer which perfoms well, 1p., April 29, 1884
14. Rockwell, A.F. Washington, DC. Opinion on the wiring of underground cable, 2p., April 30, 1884
15. Powell, J.W. Washington, DC. "Desirability of making a trial up Mt. Whitney", 4p., May 5, 1884
16. Snyder, W.B. Philadelphia, PA. Forwarding bolometer to the International Electrical Exhibition at the Franklin Institute, 1p., May 19, 1884
17. Brashear, J.A. Allegheny, PA. Langley proposes to use, in place of a concave mirror of silver copper, a flat mirror silvered on the front face in order to read the reflected scale of his galvanometer, 2p., May 21, 1884
18. Thaw, William. Allegheny, PA. Annual report [1883/84] to the Committee of the Allegheny Observatory, 7p., May 27, 1884
19. Grunow, William. West Point, NY. Encloses sketches of a new method of constructing a platinum bolometer, 2p., June 2, 1884
20. Lowny, R. Washington, DC. The abolition of the U.S. Coast and Geodetic Survey as a separate service would be a "misfortune", 1p., June 16, 1884
21. Grunow, William. West Point, NY. French people requesting one linear and one square bolometer, 1p., June 22, 1884
22. Thaw, William. Allegheny, PA. Speculated transfer of Allegheny Observatory Trust to a Massachusetts institution, 2p., June 24, 1884
23. Peal, S.E. Naharani, India. Theoretical measurement of lunar temperature, 2p., June 30, 1884
24. Mills, N. Washington, DC. Receives proof copy of pages 215 to 219 of Mt. Whitney Report, 1p., September 17, 1884
25. Brashear, J.A. Allegheny, PA. Langley requests preparation of a glass cover mirror to be used in a new spectroscope, 1p., September 27, 1884
26. Thomson, William. Glasgow, Scotland. Allegheny Observatory has obtained conclusive evidence as to the character of the ultra-red bands. Suspects that they are probably telluric, 2p., October 6, 1884
27. Brashear, J.A. Allegheny, PA. Request to assemble a "Hot Box", 1p., October 31, 1884
28. Mills, N. Washington, DC. Recommends a subject index for the mt. Whitney Report, 2p., November 3, 1884
29. Franklin, S.R. Washington, DC. Langley welcomes change to midnight as the commencement of the astronomical day, 1p., December 20, 1884
30. Grunow, William. West Point, NY. Spectro-bolometer arrived too late for "special occasion it was remodeled for", 1p., January 7, 1885
31. Grunow, William. West Point, NY. Request for two cubical vessels made of brass, 1p., February 7, 1885
32. Grunow, William. West Point, NY. Requests that an estimate of cost of siderostat be sent, 1p., February 18, 1885
33. Tyndall, John. London, England. Observatory will be conducting research on the absorption of radiant heat by water vapor, 1p., February 18, 1885
34. Brashear, J.A. Allegheny, PA. Brashear appointed to make all bolometer cases of one uniform use. Sketch of proposed changes in bolometer case enclosed, 1p., February 25, 1885
35. Holden, E.S. Determination of the amount of light transmitted by Professor Holden's wave gauge screens, 2p., ca. February
36. Grunow, William. West Point, NY. Bolometers examined are up to standard. Approximate resistances are stated, 2p., March 14, 1885
37. Hazen, W.B. Washington, DC. A discussion of most efficient method for studying the "selective absorption of solar radiant heat" Also sketch enclosed of proposed physics-meteorological laboratory, 7 p., March 14, 1885
38. Mills, N. Washington, DC. Reply to "certain meteorological researches alluded to by the New York Herald", 1p., March 16, 1885
39. Goff, M.B. Pittsburgh, PA. A brief statement of the nature of the work of the observatory addressed to the chancellor of Western University of Pennsylvania, 7p., March 18, 1885
40. Peal, S.E. Naharani, India. Concerning the direct measurement of lunar heat, 1p., June 12, 1885
41. Baird, F.S. Washington, DC. Inquiry as to whether Smithsonian Institute would assist in foreign distribution of Mt. Whitney Report prepared by Allegheny Observatory, 1p., June 26, 1885
42. Tatlock, John. Beloit, Wisconsin. States that the Allegheny Observatory was the first to establish an electric time service to railways, 2p., July 3, 1885
43. Bramwell, Frederick. London, England. Acknowledgement of receipt of communication of May 14, 1885 extending thanks to members of Royal Institution for expression of their satisfaction with discourse delivered in April 1885, 1p., July 7, 1885
44. Blanford, Henry F. Langley inquiring about the temperature of surfaces of "rock or soil, uncovered by snow, at very great altitudes", 2p., July 14, 1885
45. Whymper, Edward. London, England. Has forwarded a copy of observations on Mt. Whitney in the Sierra Nevadas which discusses primarily theoretical temperatures of airless planets, 2p., July 14, 1885
46. Julius, W.H. Utrecht, Holland. Concerning the determination of wavelengths of heat emitted from bodies below incandescence, 3p., August 14, 1885
47. Goff, M.B. Pittsburgh, PA. Making inquiry through Western Union Telegraph Co. concerning a meteor sighting, 1p., October 5, 1885
48. Science Magazine. Reports of a meteor in Western Pennsylvania on September 26, 1885 unfounded, 2p., October 7, 1885
49. Tyndall, John. London, England. Submits by mail a paper on lunar heat, 2p., October 14, 1885
50. Brashear, J.A. Allegheny, PA. Langley requests that Brashear observe "siderostat to see whether a needed adjustment can be introduced to make the telescope [Langley;s] parallel to the declination (and free from present shake)" Sketch enclosed, 2p., October 28, 1885
51. Goldback, C. Kehl, Germany. States that observatory is using rock-salt for researches on radiant heat, 1p., November 7, 1885
52. Grunow, William. West Point, NY. Requests construction of a bolometer to consist of 3 central strips each 1 mm. wide and 10 mm. in length to be made of platinum which was "heavier than usual", 1p., November 7, 1885
53. Austin, W.W. Johnstown, PA. Response to letter of inquiry requesting longitude and local time of Johnstown, 1p., November 24, 1885
54. Warner and Suazey. Cleveland, Ohio. Wishes to replace governor of siderostat driving clock, 2p., November 25, 1885
55. Brashear, J.A. Allegheny, PA. Discusses conversation with W. Thaw. Request for two 18 mm. discs. Also Langley requests Brashear's presence so that he might present him with a sketch and definite order for work to be done on galvanometer, 2p., November 30, 1885
56. Barber, D. Professor Langley wishes to purchase an economical storage battery which will be efficient in maintaining a steady dynamo current, 1p., December 1, 1885
57. Brashear, J.A. Allegheny, PA. Langley requests that the following work be executed for Allegheny Observatory: 1) construction of small mirrors for galvanometer; 2) adjustment of galvanometer back and head screw; 3) construction of scale lamp; 4) construction of siderostat and siderostat mirror; 5) construction of other mirrors. Memoranda supplying specifications and sketches enclosed, 7p., December 4, 1885
58. Brashear, J.A. Allegheny, PA. Request for a larger lens [usage not specified, Ed.] and a modification of previous order for siderostat mirror. Sketch enclosed, 1p., December 5, 1885
59. Brashear, J.A. Allegheny, PA. Request for rock-salt lens of about 75 mm, 1p., December 8, 1885
60. Achert, E.E. Denver, Colorado. Langley requests a specimen of rock "capable of furnishing a lens of nearly three inches diameter", 1p., December 10, 1885
61. Crunow, William. West Point, NY. Langley posts three carbon filaments, 2p., December 19, 1885
62. Hill, Clark Co. Boston, MA. Seeking advice concerning the efficiency of a self-starter as applied to a 4 horse otto gas engine, 1p., January 7, 1886
63. Marshall, W.H. Pittsburgh, PA. Explanation of "primary colors" A.L.S. 2p., January 7, 1886
64. Wiedemann's Annalen. Leipzig, Germany. Submitting by mail a manuscript on unrecognized wavelengths, 2p., January 9, 1886
65. Brashear, J.A. Allegheny, PA. Request for shipment of galvanometer and siderostat mirror, 1p., January 14, 1886
66. Foote, A.E. Philadelphia, PA. Request for half dozen dragonflies. [Perhaps has some relation to aerodynamic experimentation, Ed.] A.L.S. 1p., January 16, 1886
67. Brashear, J.A. Allegheny, PA. Observatory has not yet received galvanometer, 1p., January 18, 1886
68. Colby, E.A. Newark, NJ. Carbon filaments used in conjunction with galvanometer, 1p., January 19, 1886
69. Grunow, William. West Point, NY. Request for construction of a linear bolometer, 1p., January 19, 1886
70. Frost, A.G. Youngstown, Ohio. "Approximate relative positions of the Sun, the Earth and Venus in January 13, 1886 viewed from the North Side of the Plane of the Ecliptic" Sketch enclosed, 1p., ca. January
71. Brashear, J.A. Allegheny, PA. States reasons, lose of light and glare, for defects in opaque seals, 1p., February 8, 1886
72. Rise and Guager. Request for construction of one copper and one galvanized iron box. Sketches enclosed, 2p., February 8, 1886
73. White, Martin. Glasgow, Scotland. Bolometer function and usage, 1p., February 10, 1886
74. Faye, A.E. Paris, France. Requests that chief signal officer of the U.S. Army forward a copy of Volume XV of the signal service publication "Research in Solar Hear",1p., February 18, 1886
75. Hodgkins, H.L. Washington, DC. Results of computations recently made were correctly deduced from given data, 2p., February 20, 1886
76. Brashear, J.A. Allegheny, PA. F.W. Very requesting that Brashear prepare a condensing lens. L. 2p., March 4, 1886
77. Rucker, A.W. London. Bolometers not suitable for lecture demonstration, 2p., March 11, 1886
78. Ball, John. London, England. Langley posts copy of his paper "On the Amount of the Atmospheric Absorption", 1p., March 12, 1886
79. Hazen, W.B. Washington, DC. Wishes to record "the motion of a galvanometer needle by means of photography", 2p., March 16, 1886
80. Vincent, H.B. McConnelsville, Ohio. No "systematic distribution of time to places outside of Pittsburgh" by the Allegheny Observatory, 1p., March 16, 1886
81. White, Martin. Glasgow, Scotland. Request for a more sensitive reflecting galvanometer, 2p., March 16, 1886
82. Grunow, William. West Point, NY. Carbon bolometer "a mechanical success" but does not perform as well as expected, 3p., March 29, 1886
83. Ball, John. London, England. Langley discusses temperature variations of the soil of the full moon, 2p., April 19, 1886
84. Marson, G. Paris, France. Submitting by mail to Annales de Chimie et de Physique in a few days complete illustrations for an article on "Invisible Spectrum and their wavelengths", 1p., April 19, 1886
85. Thomson, William. Glasgow, Scotland. Research just completed on the relation of the index of refraction to wavelength by utilizing a mirror galvanometer, 1p., April 19, 1886
86. Western Union Telegraph Co. Pittsburgh, PA. Request for names of firms, corporations, or individuals receiving clock signals over the Western Union wires, 1p., May 8, 1886
87. Grunow, William. West Point, NY. New bloomer case received and is "very satisfactory", 1p., May 17, 1886
88. Thomson, William. Glasgow, Scotland. Soon to announce research completed in the area of the heat spectrum, 1p., May 18, 1886
89. Grunow, William. West Point, NY. Langley returning bolometer No. 4 because its "working badly having very unequal resistance" Requests its immediate return and wishes to know with what thickness of platinum it is filled, 2p., May 19, 1886
90. Gibbs, G.W. New Haven, Connecticut. Seeking counsel in area of theoretical optics, 2p., May 25, 1886
91. Darwin, G.H. Cambridge, England. Langley states that he is conducting research on wavelengths in the infrared spectrum and most probably will not be able to attend an international conference in England, 2p., May 29, 1886
92. Spoere, G.S. Potsdam, Russia. Concerning sources of solar radiant heat, 2p., May 29, 1886
93. Landslo, H. Berlin, Germany. An explanation of determination of wavelengths of infrared lines, 2p., May 31, 1886
94. Gibbs, G.W. New Haven, CT. Acknowledges thanks for assistance received in solving a problem in theoretical optics, 1p., June 7, 1886
95. Hodgkins, H.L. Washington, DC. Request for assistance in computing solution to a problem in optical physics, 2p., June 7, 1886
96. Marson, G. Paris, France. Submitting by mail to the editor of Annales de Chimie et de Physique the completed manuscript of the research referred to in the Comptes Rendus of January 18, 1886, 2p., June 9, 1886
97. Aitken, John. Edinburgh, Scotland. Langley requesting literature on the subject of nocturnal radiation, 1p., June 11, 1886
98. Grunow, William. West Point, NY. Refilled bolometer No. 14 which arrived in "good order" Several bolometers in need of repair are forwarded along with a new alloy which is said "to possess superior qualities for a bolometer." Lastly, Grunow is cited in European journals as the manufacturer of the Langley bolometer, 2p., June 11, 1886
99. Kedzee, J.H. Chicago, Illinois. A critique of a book written by Kedzee on solar radiation, 1p., June 12, 1886
100. Goff, Milton B. Pittsburgh, PA. A list of assistants at the Allegheny Observatory, 1p., June 18, 1886
101. Hodgkins, H.L. Washington, DC. Request for assistance in computing solutions to an equation. [The nature of which is unspecified, Ed.], 1p., June 23, 1886
102. Hodgkins, H.L. Washington, DC. Computations received and "appear to be satisfactory", 1p., July 24, 1886
103. Ashburne, Charles A. Philadelphia, PA. Letter with map indicating position of observatory relative to neighboring streets, 1p., July 26, 1886
104. Pickering, E.G. Cambridge, MA. "Measurement of the transmission of the Pritchard Wedge," i.e., measuring transmission of solar radiation via bolometer usage, 18p., July
105. Grunow, William. West Point, NY. Bolometer No. 13 "measured fairly near equal but neither time would the needle stay in any fixed position but went off the scale", 1p., October 5, 1886
106. Nature Magazine. Supplies Nature with an explanation of the corona of a recent eclipse, 2p., October 16, 1886
107. Grunow, William. West Point, NY. Langley requests construction of a new bolometer case with an improved eyepiece, 1p., November 1, 1886
108. Johnson, J. Pittsburgh, PA. An explanation of how and when time signals are furnished to local railroads. November 4, 1886
109. Grunow, William. West Point, NY. Ducretet's bolometer performing well, 1p., November 6, 1886
110. Hall and Sons. Buffalo, NY. Instructions for modifying construction of a crucible to be used in determining the radiation of "an entirely fixed temperature which will be given out by a piece of platinum placed at the closed end of a tub", 2p., November 16, 1886
111. Konig, Arthur. Berlin, Germany. A discussion of bolometer usage, 2p., November 17, 1886
112. Grunow, William. West Point, NY. Bolometer No. 13 "turns out to be all right". "Langley makes some slight modifications for the future construction of the bolometer thread," and inquires as to whether European orders for bolometers have increased, November 18, 1886
113. Reed, J.R. Pittsburgh, PA. Comments on Reed's mathematical theory of the bolometer, 2p., November 23, 1886
114. Grunow, William. West Point, NY. States main points of improvement for a new spectrometer for the bolometer, 2p., November 29, 1886
115. Hall and Sons. Buffalo, NY. Hoping to secure crucibles and furnace while visiting Washington, DC, 1p., December 2, 1886
116. Brown, S.C. Washington, DC. Langley extends thanks to Chief Clerk of the U.S. Dept. of State for mediation in receipt of Rumford Award by the Royal Society, 1p., December 3, 1886
117. Hall Sons. Buffalo, NY. Request for a "movable plug which can be sled up a lateral radiation tube", 1p., December 4, 1886
118. Hall and Sons. Buffalo, NY. "Please forward any work as finished", 1p., December 14, 1886
119. Rucker, A.W. London, England. Due to its sensitivity, Langley does not recommend public demonstration of bolometer, 2p., December 14, 1886
120. Rucker, Arthur W. London, England. Forwarding bolometers to the Royal Institution, 2p., December 14, 1886
121. Pickering, E.G. Cambridge, MA. Use of 5th hour meridian in determination of Pittsburgh local time, 2p., December 15, 1886
122. Thomson, William. Glasgow, Scotland. Has succeeded in getting "wonderful results" from Thomson's galvanometer, 1p., December 19, 1886
123. Hall and Sons. Buffalo, NY. Deviation from original drawing in manufacture of crucibles received, 2p., December 29, 1886
124. Brown, James. Allegheny, PA. Concerning irregular receipt of time signals by the City of Allegheny, PA, 1p., January 8, 1887
125. Ledzee, J.H. Chicago, IL. Allegheny Observatory has not "analyzed the heat radiation of any star or planet", 1p., January 10, 1887
126. White, James. Glasgow, Scotland. Request for a nonastatic needle, to measure feeble current. Full specifications of instrument supplied, 3p., January 12, 1887
127. Brashear, J.A. Allegheny, PA. Langley requests construction of a "short striding level" utilizing a transit bulb. Sketch enclosed, 1p., January 14, 1887
128. Grunow, William. West Point. NY. Gold and silver alloy bolometer not working well and is returned, 1p., January 20, 1887
129. Anthony, W.A. Ithaca, NY. Langley specifies that his bolometer is not "well adapted for lecture experimentation" and proceeds to provide dimensions for ordering a demonstration model only, 1p., January 24, 1887
130. Grunow, William. West Point, NY. Sketches and detailed explanation of design of a "strong independent mounting for the collimator arm", 10p., January 25, 1887
131. Grunow, William. West Point, NY. Submitting modifications to be made in construction of colliminator arm, 2p., January 27, 1887
132. Tinlow, G.W. Warwick, NJ. Acknowledgement of request for all names of publications dealing with the theory of the bolometer, L., 1p., February 5, 1887
133. Brill and Co. Philadelphia, PA. An order of wood of which car seats were made [possibly related to aerodynamic experimentation. E.], 1p., February 7, 1887
134. Lamansky, S. St. Petersburgh, Russia. Will forward results of investigations on the infra-red spectrum,1p., February 14, 1887
135. Grunow, William. West Point, NY. Langley wishes to refill bolometer No. 13, L. 1p., February 23, 1887
136. Gray, Thomas. Glasgow, Scotland. Awaiting with interest the announcement of the performance of a new nonastatic galvanometer, 1p., March 5, 1887
137. Hall Sons. Buffalo, NY. Not able to report on performance of crucibles which lack "plugs as their specifications demanded", 1p., March 5, 1887
138. Grunow, William. West Point, NY. Request for status of bolometers nineteen and thirteen, 1p., March 7, 1887
139. Johnston and Co. Pittsburgh, PA. Request for a heavier rubber elastic band than the one enclosed. [rubber related to flight experimentation, Ed.], 1p., March 7, 1887
140. Warner and Swazey. Cleveland, OH. An examination of the siderostat driving clock of the Allegheny Observatory, L., 2p., March 7, 1887
141. Peal, S.E. Naharani, India. Speculation of lunar temperature, a response to paper submitted to Langley by Peal, 2p., March 8, 1887
142. Powell, J.W. Washington, DC. Request for an opinion concerning Peal's lunar heat hypothesis, 2p., March 8, 1887
143. Fleuriais. Paris, France. Langley desirous to obtain a "mechanician familiar with the construction of gyroscopes", 2p., March 9, 1887
144. Glaiser, James. Blackheath, England. Request for data concerning mechanical flight, 1p., March 9, 1887
145. Johnston and Co. Pittsburgh, PA. Rubber band received buy lacking in both strength and weight. [Related to flight experimentation, Ed.], 1p., March 9, 1887
146. Rayleigh. Presently conducting experiments on the resistance of air of bodies in motion. Tequest for recommendations concerning any line of investigation likely to be of special interest, 1p., March 9, 1887
147. Thurston. Langley requests information on: first, the names of modern authorities "on air in motion at various inclinations to it"; second, the title of a modern work on wind mills; third, information of the Cunard streamers. Fourth, the name of a "really intelligent and trustworthy model-maker", 2p., March 9, 1887
148. U.S. Army, Chief Signal officer. Washington, DC. Request for information pertaining to resistance of plane surfaces to air in motion, 1p., March 9, 1887
149. Grunow, William. West Point, NY. Langley wishes to order a new bolometer to be numbered 20, L., 1p., March 19, 1887
150. White, James. Glasgow, Scotland. Modifications to be made in construction of a galvanometer. Sketch enclosed, L.,1p., March 19, 1887
151. Phillips and Co. Request for elastic rubber [probably to be used in aerodynamic experimentation, El.], 1p., March 26, 1887
152. Phillips and Co. Pittsburgh, PA. Submitting order for elastic rubber to be used in aerodynamic experimentation, 1p., March 28, 1887
153. Brashear, J.G. Allegheny, PA. Working drawings for Whirling Table nearly completed, 1p., March 30, 1887
154. Tennant, George B. Pittsburgh, PA. Modification in specification of Whirling Table, 1p., March 30, 1887
155. Specification of the Whirling Machine, A.D.S., 2p., ca. March
156. Christern, F.W. New York, NY. Request for information pertaining to cost of the publication, L'Aeronaute, 1p., April 12, 1887
157. Christern, F.W. New York, NY. Request for price of publication Histoire des Ballons by Gaston Fissandier, L., 1p., April 21, 1887
158. Brashear, J.A. Allegheny, PA. Sketch of [Whirling Table?], 1p., April 25, 1887
159. Brashear, J.A. Allegheny, PA. Experiments indicate that double wheel model [aircraft] should be discontinued and replaced by Renaud aircraft. Sketch of Renaud aeroplane enclosed, 3p., April 26, 1887
160. Queen and Co. Philadelphia, PA. Wishes to obtain a tachometer or tachograph. [Probably related to aerodynamic experimentation, Ed.], 1p., April 26, 1887
161. Phillips and Co. Pittsburgh, PA. Please state cost, width, and length of roll of elastic rubber to execute order for rubber 1/8 and also 1/4 inch thickness, 1p., April 27, 1887
162. U.S. Army, Chief Signal Officer. Washington, DC. Concerning the absolute temperature of the earth's surface and the measurement of solar radiation, 3p., April 27, 1887
163. Concerning the "true color of the sun", A.D.S., 2p., ca. April
164. Fire Department. Allegheny, PA. Complaints concerning inaccurate time signals to be directed to the Allegheny Observatory, L., 1p., May 7, 1887
165. Tennant, George B. Philadelphia, PA. Check enclosed in payment for services rendered in preparation of drawings and estimates for a Whirling Table, 1p., May 18, 1887
166. U.S. Treasury Dept., Bureau of Statistics. Washington, DC. A list of Langley's scientific papers published by the U.S. Government, L., 1p., May 18, 1887
167. Brashear, J.A. Allegheny, PA. Sketch of aeroplane [barely legible, Ed.], 2p., May 20, 1887
168. Christern, F.W. New York, NY. Second request for ordering publication L'Aeronaute, 1p., May 25, 1887
169. Thaw, William. Pittsburgh, PA. Annual Report 1886/87 of the Director, 6p., ca. May
170. Rowe, Charles O. Titusville, PA. Response to inquiry concerning time service, 1p., June 2, 1887
171. Rowe, Charles O. Titusville, PA. A "description of the devices for striking time signals" L. 2p., June 3, 1887
172. Ballot, Buys. Ultrecht, Holland. Expresses interest on status of research in the area of lunar heat, 1p., June 13, 1887
173. Clerke, Agnes M. London, England. Concerning studies on absorption of the earth's atmosphere, 3p., June 13, 1887
174. Warner and Swasey. Cleveland, Ohio. Request for a siderostat driving clock be repaired as soon as possible, L., 1p., June 14, 1887
175. Stoletow, A. Moscow, Russia. Concerning radiation analysis by means of heat spectrum and aid of bolometer, 2p., June 17, 1887
176. Queen and Co. Philadelphia, PA. Second request for ordering information pertaining to tachometer and tachograph, 1p., June 18, 1887
177. Hazen, Allen. Washington, DC. Erecting a Whirling Table of "exceptional size" to carry out experiments in anemometry and the resistance of air to bodies in motion including railroad trains. Expects to make experiments in fall with a locomotive and platform cars, 2p., June 25, 1887
178. Woodwell and Co. Pittsburgh, PA. Wishes to obtain a tachometer and dynamometer, 2p., June 25, 1887
179. Brashear, J.A. Allegheny, PA. Concerning the mounting of two large reflecting mirrors at the Allegheny Observatory, 3p., June 29, 1887
180. District Telegraph Co. Pittsburgh, PA. Wire from which railroads are receiving time signals running into several jewelry stores, 2p., June 29, 1887
181. Metzgar, Henry. Pittsburgh, PA. Serious complaints from railroads for not receiving time signals, 1p., July 2, 1887
182. Abbe, Cleveland. Washington, DC. Request for a chronograph cylinder to be used for aerodynamic experimentation, 2p., July 5, 1887
183. Rotch, A. Lawrence. Request for data on the varying velocity of the wind during short intervals of time, e.g., every quarter of minute or less. Further that Rotch request attach a chronograph to an anemometer which would record electronically the varying velocities on a uniformly revolving board, 2p., July 5, 1887
184. Rowe, Charles O. Titusville, PA. Request for a pole to be set up close to the Observatory with wires leading to the top of chromograph [Probably be used in measurement of wind velocity, Ed.], 1p., July 5, 1887
185. Grunow, William. West Point, NY. Request fro sketch of collimator and prism table, 3p., July 8, 1887
186. White, James. Glasgow, Scotland. Inquiry as to when galvanometer will be completed. No acknowledgement of letter of March 19, 1887, 1p., July 8, 1887
187. Queen and Co. Philadelphia, PA. Purchasing tachometer no. 4 running from 25 to 3000 revolutions per minute, 1p., July 12, 1887
188. Rotch, A. Lawrence. Acknowledgement of receipt of chronographic record. Requests that record should in the future be obtained on a time scale, ten times as long, "so that the changes from minute to minute can be recognized during an hour or so", 1p., July 13, 1887
189. Rowe, Charles O. Titusville, PA. Acknowledgement of receipt of pole used in connection with chromograph, 1p., July 14, 1887
190. Description of "self recording apparatus to be placed at end of arm of great Whirling Table", 8p., July 15, 1887
191. Glassford, W.O. Prescott, Arizona. Corcerning the variations of solar radiation from hour to hour, L., 3p., August 3, 1887
192. Ohio Meteorological Bureau. Youngstown, OH. Diagram of the positions of Venus, Earth, and Sun on August 14, 1887, L., 1p., August 19, 1887
193. Langley, J.A. Washington, DC. Status of research at Allegheny Observatory. Whirling Table not yet erected, L., 5p., September 10, 1887
194. Reid, H.F. Cleveland, OH. Concerning strongest current a bolometer will bear, L., 1p., September 15, 1887
195. Reid, H.F. Cleveland, OH. Specifications of bolometer, no. 1, L., 1p., September 28, 1887
196. Grunow, William. West Point, NY. Wishes to test collimator and prism table, 1p., November 8, 1887
197. De Motte, John B. Greencastle, IN. Brief description of bolometer manufacture and usage, L., 1p., November 9, 1887
198. Peal, S.E. Naharain, Sigsagar, India. Lunar research nearly completed. Findings to be issued by U.S. Government Printing Office, 1p., November 9, 1887
199. Barus. Determination of the relation between emission and temperature by spectrobolometric methods, 1p., November 23, 1887
200. Hall and Sons. Buffalo, NY. Request for a dozen crucibles. Sketch enclosed, 1p., November 23, 1887
Volume 3 Samuel Langley and Frank Very, 1887-1888
1. Smyth, Thomas H. Toronto, Canada. A bolometer might be devised to measure the temperature of a liquid, 2p., January 26, 1888
2. Thaw, William. Pittsburgh, PA. Requests permission to allow J.A. Brashear to use thirteen-inch equatorial to conduct his own research, T.L.S., 2p., January 27, 1888
3. De Motte, John B. Greencastle, IN. Forwarding information concerning bolometer theory and place and name of manufacturer of bolometer, 2p., January 31, 1888
4. De Motte, John B. Greencastle, IN. Sending two pamphlets containing illustrations and full descriptions of the bolometer and its theory, 2p., January 31, 1888
5. Reid, H.F. Cleveland, OH. Acknowledge of receipt of description of experiments with the bolometer by Professor H.F. Reid of the Case School of Applied Science, January 31, 1888
6. Brashear, J.A. Allegheny, PA. Brashear directed to prepare a scale for the "White" galvanometer. Also a request for 4 galvanometer mirrors of 1 meter values of curvature, 1p., February 2, 1888
7. Brashear, J.A. Allegheny, PA. Langley authorizes Brashear to use 13 inch equatorial of Allegheny Observatory for his own researches, 2p., February 2, 1888
8. White, James. Glasgow, Scotland. Generally pleased with finish and solardarity of galvanometer. However, hinges to enable magnets to be unclasped from glass rod were disregarded, 1p., February 2, 1888
9. Brashear, J.A. Pittsburgh, PA. Preparation of a box of seasoned pine to hold the new "White" galvanometer, L., 3p., February 3, 1888
10. Grunow, William. West Point, NY. Final modifications of dynometer - chronograph made by Brashear in Pittsburgh, T.L.S., 2p., February 16, 1888
11. Langely, S.p., Washington, DC. Very conducting experiments with humming birds, L., 2p., February 25, 1888
12. Brashear, J.A. Allegheny, PA. "Langley wishes to have made for the Smithsonian Institute a rocking case with plate glass top, mirror at sides and bottom and spring stands to hold twenty humming birds" Sketch enclosed, L., 2p., February 29, 1888
13. Abney, W. de. Wivelislile London, England. Concerning atmospheric absorption of acceptance of post at Smithsonian Institute, 6p., February
14. Sheaffer, C.W. Pittsburgh, PA. "Scarcely any current in the telegraph line", L., 1p., March 1, 1888
15. Mead, Elwood. Ft. Collins, CO. Provides ordering information for actinometer and spectrobolometer. Supplies instructions for use of instruments in place of aforementioned ones, 2p., March 5, 1888
16. Rood. Wishes to obtain data concerning the "brightness of the normal eye to the pure spectrum colors", 1p., March 14, 1888
17. Batchalde, A. Pelham, NH. Concerning the relationship between lightning and the fall of meteoric dust, L., 1p., March 21, 1888
18. Witchell. "Taking measures of the intensity of different colored lights taking for instance red, yellow, blue, or any number of other spectral colors from the same sources and same prism, and trying the comparative intensities of each by noting the relative illuminating powers by suitable tests for the normal eye", 1p., March 30, 1888
19. Pennsylvania Railroad. Altoona, PA. Posting a copy of a printed circular describing time signal distributions, L., 1p., April 5, 1888
20. McIntire, Johnston. Allegheny, PA. Langley wishes a box to be constructed to house stuffed humming birds. Sketch enclosed, L., 2p., April 28, 1888
21. Brashear, J.A. Allegheny, PA. Wishes to have a 20 inch mirror of one meter focus silvered, 1p., May 11, 1888
22. Grunow, William. West Point, NY. Concerning construction of a spectrobolometer which must be completed within ten months, 2p., May 11, 1888
23. Hale. No French engines for utilizing solar heat more recent than those of Mouchot, exhibited in 1878. French commission report engine not feasible to operate. J. Ericson's engine not economically feasible to operate, 1p., May 11, 1888
24. McIntire, Johnston. Allegheny, PA. Modifications in construction of box to contain stuffed humming birds, L., 1p., May 11, 1888
25. Reuben, Levi. New York, NY. Acknowledgement of receipt of the book, Travels in the Air. Langley states also with regard to inequalities in the distribution of clouds and rain that he cannot render a judgment on such a meteorological question, 1p., May 15, 1888
26. Thomson, W. Philadelphia, PA. Request for the title of the best treatise on color vision, L., 1p., May 24, 1888
27. Thaw, William. Pittsburgh, PA. Statement of cash receipts and expenditures of the Allegheny Observatory also includes annual report 1887/88 on the "scientific labors of the Observatory" [one page not legible, Ed.], T.L.S., 6 p., ca. May
28. Grunow, William. West Point, NY. No response concerning construction of spectrobolometer. Langley soon to depart for Europe, 1p., June 23, 1888
29. Crova, A. Montpelliar, Vermont. Concerning a new value of the solar constant. Description of galvanometer usage and sketch of galvanometer enclosed, 3p., June 25, 1888
30. Notes on the History of the Doctrine of Radiant Energy, A.D. S., 10p., ca. June
31. Grunow, William. West Point, NY. Dynomemterchronograph found to be a very satisfactory instrument but a few modifications necessary, T.L.S., 1p., July 12, 1888
32. Ticknor and Co. Boston, MA. Possibility of publishing a cheap edition of the New Astronomy in the U.S. and a costly edition in England, 1p., August 13, 1888
33. Peal, S.E. Naharani, Sibsagar, India. Commentary on the nature of the moon's rays, L., 2p., August 15, 1888
34. American Journal of Science. New Haven, CT. Enclosed copy of article entitled "Energy and Vision" for November publication, 1p., September 28, 1888
35. American Journal of Science. New Haven, CT. Concerning the return of the proof copy of an article entitled "Energy and Vision", 1p., October 23, 1888
36. London, Edinburgh, and Dublin Philosophical Magazine. Forwarding proof of an article on "Energy and Vision", which was expected to appear in the American Journal of Science for November, 1888, 1p., October 23, 1888
37. Gibbs, Wilcott. Newport, RI. Langley prepared to make a personal examination of disposition of Bache fund for purposes specified on researches in solar physics; description of research in progress, 2p., November 5, 1888
38. Brashear, J.A. Allegheny, PA. Langley providing Brashear with assistance in determining the "dispersive power" of a crown lens, 2p., November 9, 1888
39. Accounts payable for October and November, 1888, L., 1p., Allegheny, PA, November 22, 1888
40. American Journal of Science. New Haven, CT. Request for 500 copies in paper covers of History of a Doctrine, 1p., December 3, 1888
41. Ballot, Buys. Ultrecht, Holland. Will post in a few days an abstract of the paper, "On the Solar and Lunar Spectrum," published in the December 1888 issue of the Journal of Science, 2p., December 3, 1888
42. Turner, S.E. Pittsburgh, PA. Wishes to have the "shaft of the turn table made frictionless", 2p., December 3, 1888
Volume 4 Samuel Langley, Frank Very, and James Keeler, 1889-1891
1. [Memorandum] Authorization for removal of pieces of apparatus, which were the personal property of Mr. W. Thaw, to the personal charge of Langley. Signed by W. Thaw, A.D.S., 2p., June 19, 1889
2. Annual Report [1888/89] of the Director of the Allegheny Observatory, A.D.S., 4p., ca. June

Box 31
Volume 1 James Keeler, 1887-1894
Volume 2 Frank Very and James Keeler, 1892-1895
Volume 3 James Keeler, John Brashear, F.L.O. Wadsworth, and Henry Harrer, 1895-1901

Box 32
Volume 1 John Brashear, 1898-1900
Volume 2 F.L.O. Wadsworth, 1901-1902
Volume 3 F.L.O. Wadsworth, Frank Schlesinger, and Frank Bailey, 1902-1906

Box 33
Volume 1 F.L.O. Wadsworth, 1896-1902

Box 34
Volume 1-3 Frank Schlesinger, 1907-1910