10 
Of Weights and Measures . 
absolutely and relatively, which sometimes leads to very 
serious mistakes. Thus the French pinte is equal to 
nearly two English pints : the gros or eighth of an 
ounce contains 7^ grains, whereas our dram , which is 
usually reckoned as its equivalent, contains only 60 
grains : the French grain is of less absolute weight than 
the English grain, but the French inch is longer, and 
hence the same proportion does not hold in the two coun- 
tries between the measures of weight and capacity. 
The standards of weight and measure were totally 
changed in France about the year 1794, nearly at the 
time that similar changes were introduced in the divi- 
sions of the year, but though the notation of time has 
now returned to its ancient course, the system of weights 
and measures appear still to keep their ground, and are 
actually adopted in all chemical writings. It is highly 
necessary, however, to give the old, as well as the new 
system of mensuration, as the most numerous, and as yet 
the most important, researches, such as those of Lavoi- 
sier, Beaume, Macquer, &c. were made before the pre- 
sent system was adopted. 
We possess very accurate standards of comparison 
between the French weights and measures and our own, 
the old French having been carefully compared with the 
English standards by a commission from the Royal So- 
cieties of each country in the year 1752 ; and the modern 
French metre having been compared with equal accuracy 
with the English inch by Profr. Pictet in 1801. 
The old French weights and measures are the follow- 
ing : 
The pound fpoids de marc J contains 9216 grains, and is 
divided into 16 ounces, the ounce into 8 gros, and the 
gros into 7& grains : or as follows : 
