c 614 ] 
XXXII. An Account of fome Experiments made ’with an 
Air-pump on Mr. Smeaton’s Principle ; together with 
fome Experiments with a common Air-pump. By Mr. 
Edward Nairne, F. R. S. 
V 
Stead June 12, a g t h e following experiments were made 
principally to try the performance of 
Mr. smeaton’s pear-gage, it may be proper to defcribe 
it, which I fhall do in his own words, taken from the 
Phil. Tranf. for the years 1751 and 1752, vol. XL VII. 
jp* ij. 20* 
u I have found,” fays Mr. smeaton, “ the gages that 
li have been hitherto made ufe of, for meafuring the 
“ expanfion of the air, very unfit to determine in an ex- 
“ periment of fo much nicety; I have therefore con- 
u trived one of a different fort, ■which meafures the ex- 
“ panfion with certainty to much lefs than the 1 oooth 
“ part of the whole. It confifts of a bulb of glafs, fome- 
■“ thing in the fhape of a pear, and fufficient to hold 
“ about 
