1876.] 



Specific Volumes of Liquids. 



303 



pared with water at 4°. On the supposition that the liquid contracts 

 regularly below its ordinary solidifying-point, its specific gravity at 0° is 

 2*21324, compared with water at 4°. Other observers have found for 

 the boiling- and freezing-points and specific gravity of this compound : — 





Boiling- 

 point. 



Melting- 

 point. 



Specific 

 gravity. 



Eegnault . . 



131-6 at 760 mm. 



9-53 



o 



Pierre . . . 



132-6 „ 756-9 



13-1 



2-16292 at 20-79 



Haagen . . 



131-6 „ ? 





2-1827 „ 20 



Cahours . . 



130 „ ? 









Eebonl 



. f 



, , 



2-198 „ 10 



The results of the observations with the dilatometer have afforded me 

 the following formula, which expresses with sufficient exactitude the 

 rate of expansion of this liquid from 0° to its boiling-point : — 



V = 1 + 0-000 952 845 1 + 0-000 000 683 455 1 2 



+ 0-000 000 00 394 763 1 3 . 



The following Table is calculated by means of this expression ; it shows 

 the true volumes of ethene dibromide at every 5° between 0° and 135° : — 



°c. 



Volume. 



Diff. 



°0. 



Volume. 



Diff. 







100000 





75 



107697 



557 



5 



100478 



478 



80 



108262 



565 



10 



100960 



482 



85 



108835 



573 



15 



101446 



486 



90 



109417 



582 



20 



101936 



490 



95 



110007 



590 



25 



102431 



495 



100 



110607 



600 



30 



102931 



500 



105 



111215 



608 



35 



103436 



505 



110 



111834 



619 



40 



103946 



510 



115 



112462 



628 



45 



104462 



516 



120 



113101 



639 



50 



104984 



522 



125 



113750 



649 



55 



105513 



529 



130 



114409 



659 



60 



106049 



536 



135 



115080 



671 



65 



106591 



542 









70 



107140 



549 



131-45 



1-14602 





The specific gravity of ethene dibromide at its boiling-point is 1-93124, 



187*90 

 and its specific volume = TTooTol =97*295. 



Pierre, who has already determined the expansion of this liquid, found 

 that a single expression of the form 



V= 1 + at+bf + ct 3 



would not express the results of his observations with sufficient accuracy. 



