238 Proceedings of Royal Society of Edinburgh. [sess. 
the Royal Astronomical Society was represented by Mr W. IT. 
Wesley. 
To turn to the special affairs of the Scotch party. The instru- 
mental equipment consisted of the 40-foot telescope, which was 
under the special care of Dr Copeland, and was manipulated with 
great success by Mr MTherson. To me Dr Copeland kindly 
assigned the use of a new triple object-glass of 6-inch aperture, 
fitted with a whole plate camera and mounted on a heavy 
equatorial stand. Mr Franklin-Adams was armed with three 
portrait lenses, mounted in cameras to take plates of large size, 
with which he hoped to obtain photographs of the corona, showing 
the streamers to their utmost extent, and perhaps to find some 
trace of an intra-mercurial planet, if such has any existence. He 
was also provided with several ordinary cameras and a pair of long 
sensitive thermometers. 
Dr Copeland’s 40-foot telescope is well known to members of 
this Society, as it has already made its appearance at two previous 
eclipses, at one of which — the Indian Eclipse of 1898— a fine series 
of photographs of the corona and of spectra was secured. 
The 6-inch Cooke triple object-glass is a newer instrument, and 
the desirability of trying the suitability of such an instrument for 
the production of photographs of the corona was the inducement 
which led to my joining the expedition to Santa Pola. The 
object-glass and camera were constructed by Messrs Cooke of 
York, and were fitted to a brass tube in our own workshop at 
Blackford Hill. The triple, or photo- visual, object-glass is made 
up of three lenses of Jena glass, combined in such a way as to bring 
the focus of the visual rays into practical coincidence with that of 
the photographic rays, so that the telescope can be used either for 
visual or photographic purposes without alteration. The combina- 
tion is almost truly achromatic for all visual rays, the images of the 
moon’s limb, or of such stars as Yega, showing no trace of the blue 
secondary spectrum so conspicuous in all other forms of so-called 
achromatic object-glasses. The instrument was completed only a 
few days before it was necessary to pack it up for transit to Spain. 
The interval, however, during which it was mounted at the 
Observatory was sufficient to allow of the position of the focus 
being determined with great care. Several trails of stars were 
