7 EXPANSION. — 257 
aasion. vision than in the lower, and he obtained the following Notwithstanding tlie accurate experiments of M. Le- Expansion. 
SoS results: ; ths wifes i fevre’ Giana} whis proved tie! tiaxiamium density of —— 
in kid HA} Ratio of expansion in the higher water to be 39°.2, the results obtained by Mr Dalton 
TPA tesa division to that in the lower. threw a considerable degree of uncertainty over the 
=f 1 cage » + 4 + 16° to 140 subject, and chemists were divided in their opinions, 
_ Olive oil, . woe woe Bs - 13.4 till the subject was investigated by Dr Hope in a Experi- 
: Linseed oi], . . . oe 1s) ‘ 184 new manner, which was not li to any error ments of Dr 
Chamomile oil, ... . «4 15 13.0 — arising from the contraction of the containing ves- 4r 
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2 
Waters po. (tee ah Botan 4.7 the expansion might be rendered visible by the change 
Anomaly in © The results for water contained in the last cflumn  % Place, which would happen in a column of water when 
7 s gs from 
the Table, exhibit a very 
REE 
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i 
43 broad, with water at the temperature of 62°, and 
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58 
358% 
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© tes thes , in the most the surface was always one d lower than the one at 
been. shewn, in thatthe density of the water 
: 
ik 
is not 
ter be free of all agitation so as to prevent it from adjusted at the middle of its height a bason of tin- 
r be Kept and is cooled down’ to 21° or 220, Nediron, by filling »which, either with hot water, or 
the jon still alia . ing ratio.  frigorific mixture, he could apply heat or cold to the 
Mr f ¥ Rie: a sn aiteintan th 494° middle of the fluid pe Rey A thermometer 
of Fak I it; he f 1 that the nsi nm was scarce- at the and bottom of the jar as before, 
perceptible from 41° to 44°, and that from 41° to 32° the jar was filled wi water at 32°, and water of the 
the ion was about +2,th part of the whole expan- temperature of 68° ee into the bason of tin- 
sion from 424° to 212°, neces Deluc’s observa- "€4 iron. The lower thermometer rose from 32° to 
tion, that. the for any number of degrees nearly 37° before the upper thermometer indicated the 
éither shove or below 424° was the sane but he after. mullest increase of temperature, the warm current 
wards thought that it was below 42°. He also baving moved downwards in consequence of the con« 
verified the ok ion of Sir Charl that the ‘*taction or increase of density of the water. Dr H. 
: continaée % Blagdon, A reversed this experiment by ling the basom with 
coolithr 1¢'66 fara in a tube, that the water had ex- ‘rigorific mixture, while water in the jar had a 
and risen to the same height as if it had been *e™perature of 39}°. The upper thermometer descen- 
ed to 75. Hence, it must have been cooled down So while the lower 
to 10°. soon as it was frozen, it up to 128°, One su . a » the current of cooled 
\ These remarkable appearances wereregarded by seve: Water. ascending to the tp of the jr. By thas vary 
~ ex ina ilful 
zal philosophers as so anomalous, that they were probably a Dr Hope decided — engge y+ = 
: uestion of the maximum 
ments ; and even Mr Dalton himself was induced tobe- ‘ensity of water, and is entitled to the honour of ha- 
lieve, that the anomaly exhibited by water was only Ly. hig, the first who really established the existence 
apparent, and arose from. the contraction of the vessel gypenaly. 
sestigts Unie poe he aapeded tne. nears es msing Moxsicar.Acopo.ot-Pasis tn in cee of te SS 
ve ; at Paris in course o: fM, 
earthen ware and metallic vessels, and com the summer, he mentioned to him a series. of experiments Arzo.. r 
remults with those made in glass. In all these trials, ™atle on the reftactive power of water at different tem- 
the point of maximum density, instead of being the ee =a fill if its maximum densi- 
| e, varied with each substance, as will appear from ‘Y Was above 32°. He filled a prism with water at the 
'. . the following Table : tem wiry del a ha 9 ere ee angle of deviation 
; Water the refraction, w its tem ti fi 
Meet | come 32° to 212°. ‘The angle of deviation Was greater at 32°, 
height. it gradually diminished to 212°, exhibitin k 
Brown earthen ware, No. t. at $6° at $2° and 40° whatever of a variation of refractive power at 40°, or at 
Brown earthen ware, 0.2. °38 34 44 any point between 32° and 212°. Hence Monsieur 
Queen’s ware, - . 40 82 48 Arago concluded, that since the refractive power always 
= i) shin 41 $2 51 _ increases with the density, the density of water must 
ton, thin p p $2 53 at a maximum at 32°. This conclusion might have been 
Copper. ‘ 32. 59 admitted to have considerable weight, Dr Hope 
pe pow Ser - 46 _ 820 60. had established the ite conclusion by direct expe- 
pita : ris “ ms riment ; but, it of this circumstance, we have 
VOL. IX. PART 1. no hesitation in saying, ol M. Arago’s conclusion is 
te 
