302 ' History of Chemical Discoveries. 
tained nearly as perfect as the Torricellian one, because the mer- 
cury was carefully dried, and some pieces of chlorure of calcium 
introduced into the tube, to absorb the humidity. When it 
was required to augment the vacuum, the extremity of the 
mercurial column was brought near the ball of the thermome- 
ter, and when the temperature was seen to be permanent, the 
cistern was rapidly brought down, in the third of a second, and in 
order to diminish the vacuum, the cistern was raised by turning 
the winch. But though the vacuum was reduced from about a 
litre to one-fourth of its volume, or vice versa^ the air-thermo~ 
meter never indicated the slightest variation. As soon, how- 
ever, as a small quantity of air was introduced, very sensible 
variations of temperature took place, by compressing or dila- 
ting the barometrical space. Hence we may conclude, that a 
vacuum does not contain caloric like bodies in general. It is 
only therefore caloric in motion which exists in a vacuum, du- 
ring the short time that it takes to pass through it in the form 
of radiant heat. — Abridged from the Ann. de Chim. tom, xiii. 
p. 304. 
III. Observations on Oily Substances. By M. Theodore de 
Saussure. 
As our limits will not permit us to give a detailed account of 
this interesting paper, we must confine ourselves to a general 
view of the results obtained by its able author ; referring for 
the paper itself to the Bibliotheque Universelle^ Jan. 1820, 
p. 20—42. and Feb. 1820, p. 112—135. 
Substances 
Examined. 
^Carbon. 
Hydro- 
gen. 
Oxy- 
gen. 
Azot, 
Original Den- 
sity. 
Density when 
distilled. 
Essence of lemons, 
86.899 
12.326 
__ 
0.775 
0.8517 
0.8471 at 22° 
turpentine, 
87.788 
11.646 
— 
0.566 
— 
0.86 j cent. 
lavender. 
75.5 
11.07 
13.07 
0.36 
0.898 
0.877 at 20°. 
camphor. 
74.38 
10.67 
14.61 
0.34 
— 
0,988 
rosemary 
82.21 
9.42 
7.73 
0.64 
0.9109 at 15° 
0.8886 
anise, com- ) 
76.48 
9.352 
13.821 
0,34 
0.9857 at 25° 
mon, j 
concrete. 
83.468 
7.531 
8.541 
0.46 
— 
0.9849 
— — roses, com- ) 
82.053 
13.124 
3,949 
0.877 
0.832 
mon, / 
concrete. 
86.743 
14.889 
— 
— , 
— 
Purified bees^ wax. 
81.607 
13.859 
4.534 
— 
0.966 when 
fixed. ! 
0.834 at 81° 
75.474 
12.795 
11.377 
0.354 
— 
Margaric acid. 
70.95 
12.635 
16.415 
— 
1 1.01 solid. 
0.854 at 94° 
