II. An Account of a Book , intit led, P. D. Pauli 
Frilii Mediolanenfis, &c. Difquifitio ma- 
thematica in caufam phylicam figure et 
magnitudinis Telluris noftrae ; printed at 
Milan in 1752. infcribed to the Count de 
Sylva, and confjling of Ten Sheets and a 
half in Quarto: By Mr .. J. Short, F, R. S*. 
Read Jan. 18, i.TT may be laid down as a rule in 
17S3> JL mix’d mathematics, “ That the de- 
#t termination of no phyfical quantity be carried far- 
<c ther than the obfervations, or other mechanical 
ct meafures, can bear y left there follow this incon- 
gruity, of the concluiion being more extenfive than 
the premifes. It were abfurd, for in dance,, in the 
refolution of a triangle, to compute an angle to the 
exadtnefs of feconds, or a fide to centefms of an inch, 
when,, perhaps, the inflruments ufed can meaiure no 
angle lefs than 10 minutes, or a fide but to the ex- 
a&nefs of a foot. The conclufions of arithmetic and 
geometry are indeed rigoroufly true, but they are only 
hypothetical y and whenever the quantities,, that enter 
any pra&ical queftion, cannot be meafured, but with- 
in certain limits, it were in vain to look for an an- 
fwer perfectly accurate .. The error of the inftrument 
becomes itfelf one of the data y and we mud con- 
tent ourfelves to find the limits, which the quantity 
fought cannot well exceed, or fall fhort of, by fuch 
rules, as the great Mr. Cotes has left us in his excel- 
lent treatife on the fubjedf. 
2. In 
