C 2 9 6 ] 
EXPLANATION. 
The prlncip il table confifts of three columns. The numbers in the 
firft column fignify degrees, either of dk luc’s fcale, or the fcale which 
hath been hitherto chiefly in ufe among che French, which is divided as 
M. de luc’s is ; but 28 French inches being generally mentioned, by the 
French mathematicians, as the mean height of the barometer at r a ris, it is 
to be fuppofed, that their boiling point will generally agree to that date of 
the barometer. The numbers in the next column to the right, which is 
marked L reduced , give the degrees of bird’s Fahrenheit correfponding 
to the degrees cf M. de luc’s fcale, exprefled by the numbers of the 
firft column ; and the numbers in the column marked P reduced, give the 
degrees of bird’s Fahrenheit correfponding in like manner with the 
paris fcale. The heights in the firft column diminilh by 5 0 fucceflively. 
But the redu&ion may be computed to every degree, by means of the 
little table on the left; which gives the value of Angle degrees, either 
of de luc’s, or of the paris fcale, in degrees of bird’s Fahrenheit. 
The titles LF, PF flgnifying de luc’s degrees, or Paris degrees, re- 
duced to Fahrenheit’s, refpeftively. 
If there fhould be occafion to reduce heights of bird’s Fahrenheit, 
either to M.de luc’s, or the paris fcale, this maybe done by the prin- 
cipal table, and the fmall one on the right hand; which exhibits the 
value of Angle degrees of bird’s Fahrenheit in degrees, both of de 
luc’s and the' Paris fcales : the titles F L, FP flgnifying degrees of 
bird's Fahrenheit reduced to M. de luc’s degrees, or the pa ris de- 
grees, refpeftively. 
-example. 
EXAMPLE 2. 
To find the point upon a bird’s 
Fahrenheit, which correfponds to 
+ 58 of de luc’s fcale. 
To find the point upon the Paris 
fcale, which correfponds to -p 55 
of bird’s Fahrenheit. 
By principal table -f- 55 = 154,3; 
By little table on ] 
the left hand | 
3 = 6,67 
Therefore 58 = 161,04 
7 By principal table 
55 ~ 5'4>45=<MS 
By little table on 1 
the right hand J 
By ditto - - - 
+ 54>45 = 10 
0,5 = 0,22 
0,05= 0,02 
Therefore +55 =10,24 
TABLE 
