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Received November 9, 17 69. 
X. Account of fome Improvements made 
i?i a new IVheel Barometer , invented by 
Keane Fitz Gerald, Ef quire , F. R. S. In 
a Fetter to Charles Morton, M. D . Sec . 
& 
Dear Sir, 
Read Feb. 22, t G A V E a former defcription and 
drawing of a wheel- barometer of a 
new conflruCtion, with regifiers to mark the rife and 
fall of the mercury, which were publifhed in the 
firlf part of the fifty-fecond volume of the Philo- 
fophical TranfaCtions for the year 1761. As that 
iuftrument has continued to operate effectually by 
the weight of a few grains only, and the regifters to 
mark the limits of the afcent and defcent of the 
mercury in the tube very cxaCtly ever fince, it has 
induced me to attempt a further improvement, which 
I have alfo found to anfwer effectually ; and take the 
liberty of defiling the favour of you to lay a defcrip- 
tion and drawing of it before the gentlemen of the 
Royal Society, if you think a communication of the 
kind worth their notice. 
As 
