PHILOSOPHICAL TRANSACTIONS. 
XIL An Account of Meteorological Ohservatims in Four Balloon Ascents, made 
under the direction of the Kew Observatory Committee of the British Association 
for the Advancement of Science. By John Welsh, Esq. Communicated by 
Colonel Sabine, R.A., Treas. and F.P.R.S., by the request of the Council of the 
British Association for the Advancement of Science. 
Received April 27,— Read May 26, 1853. 
In July 1852 , the Committee of the Kew Observatory resolved to institute a series 
of balloon ascents, with the view of investigating- such meteorological and physical 
phenomena as require the presence of an observer at a great height in the atmosphere. 
The arrangements made for carrying out this resolution have been stated by the 
Committee in their report to the Council of the British Association, a short account 
being at the same time given of some of the results derived from the ascents already 
made. Having been to a great extent entrusted by the Committee with the conduct 
of the observations and with the instrumental arrangements, I now, at their request, 
proceed to give a more detailed statement of the mode in which the experiments have 
been made, and of such results as may most readily be deduced from the observa- 
tions recorded in the ascents. 
The object to which especial attention was devoted, was the determination of the 
temperature and hygrometric condition of the air at different elevations above the 
earth s surface. Besides this, the observers were furnished with the means of pro- 
curing specimens of the air at different heights for the purpose of analysis, and of 
examining, if opportunity offered, whether the light reflected from the upper surface 
of the clouds was polarized. 
§ 1 . Instruments and Apparatus. 
The instruments required for the investigations contemplated were — a barometer; 
dry and wet thermometers ; an aspirator ; Regnault’s condensing hygrometer ; 
Daniells dew-point hygrometer; a polariscope ; and glass tubes, furnished with 
MDCCCLIII. 9 q, 
