XXXVI REPORT—1857. 
effected by approaching to, or withdrawing from, a hollow cone over a small 
wheel, on which are attached, by means of flat springs, two small weights, 
which expand by centrifugal force and come in contact with the inside of the 
hollow cone. 
The polar axis of the telescope is carried by a dial-plate, which fits on the 
top of a hollow column of cast iron, the section of which is a parallelogram. 
This column is securely fastened to the stone foundation. The instrument is 
mounted within the rotating dome of the Kew Observatory, which has been 
repaired and put in order for that purpose. The photographic dark room is 
at present too distant from the telescope, but it is contemplated to construct 
one close to it, as serious inconvenience has been already experienced in the 
preliminary experiments in consequence thereof. 
The telescope and its mechanical appliances may be said to be perfect so 
far as they go, but experience will undoubtedly suggest several minor alter- 
ations and additions before the telescope is brought practically to work. The 
photographing of such minute objects as the sun’s spots will require at all 
times the utmost skill and care of an accomplished photographer, even when 
the telescope has been fairly started. The difficulties yet to be mastered must 
occupy some considerable time. The first attempts have been confined to the 
production of negative photographs, but in consequence of the imperfections 
always existing in the collodion film, it has been deemed advisable to make 
attempts to produce positive pictures, and recourse may ultimately have to 
be made to the Daguerreotype process. 
The verification of Meteorological Instruments has been continued on the 
same plan asin previous years. The following are the numbers of instruments 
which have been verified since the last meeting of the Association :— 
Baro- Thermo- Hydro- 
meters. meters, meters. 
For the Admiralty ................0... 127 840 605 
For the Board of Trade................ 86 360 140 
For Opticians and others ...........5.. 65 324 6 
Total .o.. 2 deck e042 Fs 04% 978 1524 751 
Mr. Stewart having left the Observatory, as mentioned in the last Annual 
Report, the Committee in October last engaged Mr. Charles Chambers of 
Leeds, on the recommendation of the Council of the Society of Arts. The 
Committee report very favourably of the intelligence and assiduity with 
which he has discharged his duties. 
Joun P. Gassior, 
Chairman. 
