in order to afcertain the height of Mountains. 571 
Multurn egerunt , qui ante nos fuerunt , fed non per ti- 
ger unt: mult uni adhuc reflat operis , multumque rejlahit\ 
nec ulli nato pofl mille facula pracludetur occafto aliquid 
adhuc adjiciendiP sen. Epift. 64. 
PART II. 
I N the fubfequent pages, which I have now the ho- 
nour of laying before the Royal Society, I have drawn 
up, and I hope in a form the moft commodious, the ne- 
ceffary tables and precepts for calculating any acceffible 
heights or depths from barometrical obfervations, and 
without which I thought the preceding memoir would 
be incomplete ; referring, however, to that for the proofs 
or elements from whence the tables have been com- 
puted. And herein I have endeavoured to adapt myfelf 
to the capacity of fuch perfons as are but little conver- 
fant with mathematical computations, but who may have 
frequent opportunities of contributing fomething to the 
advancement of fcience by experiments with this ufeful 
4 E 2 inftru- 
