6 SO 
EXPANSION, 
sary tq cause a liquid to boil, the smaller the 
expansion is which is produced by the addi- 
tion of a degree of heat; or, in other words, 
the expansibility of liquids is nearly inversely 
as their boiling temperature. 
Another circumstance respecting the ex- 
pansion of liquids deserves particular atten- 
tion. r \ lie expansibility of every one seems 
to increase with the temperature ; or, in 
other words, the nearer a liquid is to the 
temperature at which it boils, the greater is 
the expansion produced by the addition of a 
degree of caloric; and, on the other hand, 
the farther it is from the boiling temperature, 
the smaller is the increase of bulk produced 
by the addition of a degree of caloric. Hence 
it happens, that the expansion of those 
liquids approaches nearest to equability whose 
boiling temperatures ar ■ highest ; or, to speak 
more precisely, the ratio of the expansibility 
increases the more slowly, the higher the 
boiling temperature. 
These observations are sufficient to show, 
that the expansion of liquids is altogether un- 
connected with their density. It depends 
upon the quantity of heat necessary to cause 
them to boil, and to convert them into elastic 
fluids. But we are altogether ignorant at 
present of the reason why different liquids 
require different temperatures to produce 
this change. 
The following table will give the reader a 
precise notion of the rate of expansion of those 
liquids which have been hitherto examined 
by chemical philosophers. 
On the supposition that metals expand 
equably, the expansion of a mass of metal, by 
being heated a given number of degrees, is as 
follows: Let a — the expansion of the mass in 
length for °, which must be found by experi- 
ment'; b ~ the number of degrees whose 
expansion is required ; ^i=the solid contents 
of the metallic mass ; x = the expansion 
sought ; then x = 3 b a s. , 
The property which bodies possess of ex- 
panding, when heat is applied to them, has 
furnished us with an instrument for measuring 
the relative temperature of bodies. See 
Thermometer. 
Having considered the phenomena and 
laws of expansion as far as they are under- 
stood, it will be proper to state the excep- 
tions to this general effect of heat, or the 
cases in which expansion is produced not by 
an increase, but by a diminution of tempera- 
ture. These exceptions may be divided into 
two classes. The first class comprehends 
certain liquid bodies which have a maximum 
of density corresponding with a certain tem- 
perature ; and which, if they are heated above 
that temperature, or cooled down below k, 
undergo in both cases an expansion or in- 
crease of bulk. The second class compre- ; 
bends certain liquids which suddenly become 
solid when cooled down to a certain tempe-. 
rature; and this solidification is accompanied 
by an increase of bulk. 
Water furnishes us with the most remark- 
able example of the first class of bodies. 1 ts 
maximum of density corresponds with 43°. 5 
of Fahrenheit’s thermometer, as has been 
lately ascertained by Mr. Dalton. If it is 
cooled down below 42°.5, it undergoes an 
expansion for every degree of temperature 
which it loses; and at 32° the expansion 
amounts, according to Mr. Dalton, to ^ 
of the whole expansion which water undergoes 
when heated from 42°. 5 to 2 1 2°. With this 
more recent experiments coincide very nearly; 
for by cooling 100000 parts in bulk of water 
from 42°.5 to 32°, they were converted to 
100031parts. We are indebted to the ingenuity 
of Mr. Dalton for the discovery of a very un- 
expected fact, that the expansion of water is 
the same for any number of degrees above or 
below the maximum of density. Thus if wel 
heat water ten degrees above 42°. 5, it occu- 
pies precisely the same bulk as it does when 
cooled down ten degrees below 42°.5. There- 
fore the density of water at 32° and at 53° is 
precisely the same. Mr. Dalton succeeded 
in cooling water down to the temperature of 
5° without freezing, or 37°. 5 below the maxi- 
mum point of density; and during the whole 
of that range, its bulk precisely corresponds 
with the bulk of water the same number of 
degrees above 42°. 5. Thus the bulk of water 
at 5° is the same as the bulk of water at 80°. 
The scale of expansion, therefore, which lias 
been given for the expansion of water when 
heated, answers also for its expansion when 
cooled, provided the table begin at 42°.5, as 
is done in the table of the expansion of water, j 
From this table it appears that the expansion 
of water, the original bulk being 10000, may 
be expressed pretty nearly by the following 
numbers : 
Temp. 
Expan, 
82°. 5 . 
. . 6. 2 
102°. 5 . 
. . 8 2 
122°. 5 . 
. . 10 2 
142°. 5 . 
. . 12 2 
162°. 5 . 
. . 14 J 
Temp 
Mercury 
| Linseed 
j oil. 
Sulphuric 
acid. 
Nitric 
acid. 
Water. 
Oil of tur- 
pentine. 
Alcohol. 
30° 
100000 
100000 
— 

.. 
1 00000 
40 
100081 
— 
99752 
99514 
— 

1 00539 
50 
100183 
— 
100000 
100000 
100023 
100000 
101105 
60 
100304 
— 
100279 
1004S6 
100091 
100460 
101688 
70 
100406 
— 
100558 
100990 
100197 
100993 
102281 
80 
100508 
— 
100806 
101530 
100332 
101471 
102890 
90 
100610 
— 
101054 
102088 
100694 
101931 
103517 
100 
100712 
102760 
101317 
102620 
100908 
102446 
104162 
1 10 
100813 
— 
101540 
103196 
— 
1 02943 

120 
100915 
■ — 
101834 
103776 
101404 
103421 
— 
130 
101017 
— 
102097 
104352 
— 
103954 

140 
101119 
— 
102320 
105132 
— 
104573 

150 
101220 
. — 
102614 
— 
102017 

160 
101322 
— 
102893 


. 
170 
101424 
— 
103116 


180 
101526 
— 
103339 
— 

. 
__ 
190 
101628 
— 
103587 

103617 

200 
101730 
— 
103911 



212 
101835 
107250 
— 
— 
104577 
— 
— 
r he expansion of solid bodies is so small, that a micrometer is necessary to detect the 
met ease ot bulk, - As far as is known, the expansion is equable, at least the deviation 
from perfect equality is insensible. The following table exhibits the expansion of most 
ot i he solids which have been hitherto examined. Most of the experiments were made 
by bmeaton. 
Temp. 
Platinum. 
Antimony 
Steel. 
Iron. 
Cast-iron. 
Bismuth. 
32° 
212 
White- 
120000 
120104 
120000 
120130 
120000 
120147 
120000 
120151 
120000 
120000 
120167 
heat 
123428 
121500 
122571 
Copper. 
Cast-brass: 
Brass wire 
Tin. 
Lead. 
Zinc. 
32° 
212 
120000 
120204 
120000 
120225 
120000 - 
120232 
120000 
120298 
120000 
120344 
120000 
120355 
Hammer- 
ed zinc. 
Zinc 8. 
Tin 1 . 
Lead 2. 
Tin 1. 
Brass 2. 
Zinc 1. 
Pewter. 
Copper 3. 
Tin 1. 
32° 
212 
120000 
120373 
120000 
120323 
120000 
120301 
120000 
120247 
120000 
120274 
120000 
120218 
The expansion ol glass is a point of great importance, as it influences the result of most 
experiments on temperature. It has been examined with much precision by M de Luc. 
I iterate ol its expansion, as settled by that philosopher, may be seen in the following table : 
Temp. 
32° 
50 
70 
Bulk. 
Temp. 
Bulk. 
Temp. 
Bulk. 
100000 
100° 
100023 
167° 
100056 
100006 
120 
100033 
190 
100069 
100014 
150 
100044 
212 
100083 
* iau lc ii appears, mat wnen glass is Jieateci oi 
sion which amounts nearly to of the whole bulk. 
