EX P
E X P
55 i
pansion oi' tho=e liquids which have been hitherto examined bycliem.cal philosophers.
Temp.
Mer-
cury.
30°
100000
40
100081
50
100*33
GO
100304100406
70
80
100508
90
! l 00610
too
■100712
110
■100813
120
'100915
130
'1 010 l 7r
140
101119
150
101220
160
•101322
170
101424
180
■101526
190
101628
200
101730
212
101835
Lin- | Sill-seed oil phmicI acid.
- 9 >752
-100000
- 100279
-- 100558
-1QOSOb
-101054
102760 101517
-10154:
-! 101834
- 1 10209?
-402320
-102614
-102893
- 103116
-103339
- 103587
-103911
107250-
Nitric
acid.
Water.
99514!10000010048610099o!101530!1020S8 :102620 !1031961037761104352
100023
100091
10019?
100332
100694
1009OS
10140-1
105132
102017
10361:
104577
Oil oflurpentine.
103000100460100993101471i"I931102446,102913103421!03954104573
Alco-
hol.
1000001005391011051016881022S110289310351710416
The expansion of solid bodies is so small, that a micrometer isnecessary to detect the increase of bulk. As far as is known, theexpansion is equable, at least the deviation from perfect equality isinsensible. The following table exhibits the expansion of most ofthe solids which have been hitherto examined. Most of the ex-periments were made by Smeaton.
Temp.
bulk
Temp.
Bulk.
Bulk.
32°
100000
100°
100023
* 0/
100056
50
100006
120
100033
190
100069
70
100014
150
100044
212
100083
,
'
Plati-
num.
Anti-
( mony.
Steel.
1
Iron. 1 Cast-j iron.
. 32°212Whiteheat.
120000
1.20104
120000
120130
120000
120147
123428
1
I200Q0120000
12015F
121500 122571
1
120000
120167
Cop-
per.
Cast-
brass.
lira? -wire.
Tin. | Lead.
Zinc.
32°
212
120000
124204
120000
120225
120000
120232
1
I20Q00!J200Q012029&| 120344
120000
120355
Hammereel zinc.
32°
212
120000
120373
Zinc. 8.Tin 1.
120000120323
Lead 2.Tin 1.
Brass 2.Zinc 1.
'120000120301
120000
120247
Pewter. Copper3.tin 1.
120000120274
1200001202 IS
The expansion of glass is.a point of great importance, as it in-fluences tiie result ot most experiments on temperature. It hasbeen examined with much precision by M. de I.tic, The rate ofits expansion, as settled by that philosopher, may be seen in (liefollowing table <
From this table it appeal's, that when glass is heated one degree,it undergoes an expansion w hich amounts nearly to ot the
whole bulk. O11 the supposition tnat metals expand equably, theexpansion of a mass of metal, by being healed a given number ofdegrees, is as follows: let a = the expansion of the mass inlength tor °, which, must be found by experiment; b — the num-ber of degrees whoso expansion is required ; s — the solid con-tents of tlie metallic mass; x= the expansion sought ; then 1—3b a s. The property which bodies possess of expanding, whenbeat is applied to them, has furnished us with an instrument formeasuring the relative temperature of bodies. See Thermome-ter . Having considered the phenomena and laws of expansion asfar as they are understood, it will be proper to state the excep-tions to this general effect ot heat, or the cases in which expansionis produced not by an increase, but by a diminution of tempera-ture. These exceptions may lie divided into two classes. Thelirst class comprehends certain liquid bodies which have a maxi-mum of density corresponding with a certain temperature ; andwhich, if they are boated above that temperature, or cooled downbelow it, undergo in both cases an expansion or increase of bulk.The second class comprehends certain liquids w hich suddenly be-come solid when cooled clown ton certain temperature; and thissolidification is accompanied by an increase of bulk. VVater fur-nishes us with the most remarkable example of the first class ofbodies. Its maximum of density corresponds with 42".5 ofFahrenheit's thermometer, as lias been lately ascertained by Mr,Dalfon. If it be cooled down below 42°.5, it undergoes an expan-sion for every degree of temperature which it loses; and at 32° theexpansion amounts, according to Mr. Dalton, to of the wholeexpansion which water undergoes when lieated from 42°.5 to 212°.With this more recent experiments coincide very nearly: for bycooling 100000 parts in bulk of water, from 42°.5 to 32°, they wereconverted to 100031 parts. We are indebted to the ingenuity of Mr.Dalton for (lie discovery of a very unexpected fact, that the ex-pansion of water is the same for any number of degrees above orbelow tlie maximum of density. Thus it we beat water ten degreesabove 42°.5, it occupies precisely the same bulk as it does whencooled dow n ten degrees below 42.5. Therefore the density ofwater at 32° and at 53° is precisely the same. Mr. Dalton suc-ceeded in cooling water down to the temperature of 5° withoutfreezing, or 37°.5 below'tlie maximum point ot density; and dur-ing the whole of that range, its bulk precisely corresponds with thebulk of water the same number of degrees above 42°.5. 'Finis tliehulk, of water at 5° is tlie same as the bulk ot water at 80°. 'l'liescale of expansion, therefore, which has been given tor the expan-sion of water when lieated, an-wers also for its expansion whencooled, provided tlie table begin at 42°.5, as is done in the (aide ottlie expansion of water. From ibis table it appears that the expan-sion of water, tlie original hulk being 10000, may be expressedpretty nearly by tlie following numbers:
Temp. Expan.
82°. 5. 6 s
102°,5. 8"
122°. 5.10*
142“. 5.12-
162°, 5.hi*
'Flie. greatest deviation from tbe-e. numbers is towards the begin-ning of the scales, when owing to. the smaHn.es'. of the expansion, itis ditlicuU to measure it with .precision, it leaik us to this re-markable, conclusion, that the square* of the natural numbi.s l e-ginuing at 6indicate the increase of bulk which HK'OO parts i f wa-ter e_xpenep.ee for every, ten degrees they are lieated above 82°.5,or cooled lie low 12°.5. This rule will give the reader a more pre-cise itlca of. the. rate at w.liic li water expands, when heated or cooled,than a bare inspection of the table could <lo. A considerable
number