1817.] Dilatation of Liquids at all Temperatures. 367 
from Mr. Cavendish’s discussion respecting Hutchin’s experiments 
at Hudson’s Bay. 
We see from this that the oil in cooling to any degree whatever 
cannot have an apparent maximum condensation (as is the case 
with water), at least in glass tubes. This is shown by our formula ; 
for this maximum would take place when 
d Dr 
dT 
= 0 
This gives us 
0 = 0950667 + 0:0015 T — 0:000005 T* 
an equation the roots of which are 
= sie ry’ = + errr 
That is to say, that if the oil could remain liquid at these tempera- 
tures, and continued to dilate according to the same law, it would 
have an apparent maximum of condensation when cooled down 
311-1 below 0, and an apparent maximum of dilatation when 
heated to 611°1 above zero. But these points are too much beyond 
the limits of the observations on which our calculations are founded 
to warrant the extension of the formula to them. We may con- 
clude that olive oil, as long as it remains liquid, continues to con- 
dense by cooling, and that it freezes without dilating, as is con- 
firmed by observations. 
Let us now proceed to the essential oil of camomile. For it we 
have 
D, = 09204416 T + 0°0013056 T? — 0:000003889 T° 
The following table shows the agreement of the results of the 
formula with observation :— 
7 
Mercurial Degrees of the oil of camomile 
Liquid, thermo- thermometer. 
meter, 
‘z Calculated. | Observed. | Difference. 
80 §0:00 80:0 0°00 
70 69°49 69°5 +001 
60 59°09 BY }a +0°01 
Essential 50 48°80 48°8 0:00 
oil of 40 38°66 38°6 — 0-06 
eamomile 30 28°63 28°7 —002 
.20 18°90 18°9 0:00 
10 9°30 9°3 0°00 
0 0°00 0:0 0°00 
We see that in this case the formula is as exact as observation 
