368 SEC. 11. ASTRONOMY. 



1860a. Photographs of the Arrangement for Obtaining 

 Solar Photographs, by means of Huyghen's lens of 123 feet 

 focal length. J. Norman Lockyer, F.R.S. 



1861. Photographs of the least refrangible end of the spec- 

 trum, by iron and other processes. Capt. Abney, R.E. 



1862. Daguerreotype of the Total Eclipse of the Sun 



of the 28th of July 1851, taken at the Observatory of Konigsberg. 



Dr. Rchur, Strassburg. 



During the eclipse four photographs were taken. This one was formerly 

 in the possession of Prof. A. C. Petersen, late Director of the Observatory 

 in Altona, and after his death it became the property of his grandson, the 

 exhibitor. 



1863. Photographs of the Sun, taken with the Kew helio- 

 graph, and one of a scale put up for determining the amount of 

 distortion produced by the instrument. 



Kew Committee of the Royal Society, Kew Observatory. 



The Kew Observatory possesses a set of these negatives, extending from 

 1858 to 1872, and it is now employed in accurately determining from them 

 the positions and areas of the spots observed during the 10 years 1862-1872, 

 during which they were uninterruptedly obtained. 



They are photographed on collodion fibrine, and developed by pyrogalHc 

 acid. 



The sixth picture in the frame is one of a series of views taken, of a 

 standard scale, suspended to one of the galleries of the Pagoda in the Kew 

 Gardens, distant 1,500 yards, for the purpose of determining the optical dis- 

 tortion of the heliograph. 



18 63 a. Photographic Normal Spectrum of the Sun. 



Collection of enlarged comparison photographs, used in the 

 research. J. Norman Lockyer, F.R.S. 



1863b. The Solar Spectrum. Photograph, showing its ab- 

 sorption lines, by George Rutherford, of New York. 



Robert James Mann, M.D. 



The entire blue part of the spectrum is divided into sections, which are 

 mounted above each other. When these are placed together in their proper 

 continuation, the spectrum is nearly 8 feet long. 



1863c. Photographic reproduction of the Solar Spec- 

 trum in its natural colours. First proofs obtained by M. E. 

 Becquerel in 1848. (This proof, enclosed in a box, must be pro- 

 tected from the light.) M. E. Becquerel. 



1864. Photographs of the less refrangible parts of the sun's 

 spectrum, from line E downwards. 



Professor H. W. Vogel, Berlin. 



(3.) Photograph of a larger spectrograph, which, being in use, could not 

 be spared for this exhibition. The accompanying photographs of the solar 



