20t8 On the Expanfion of Aids by Heat. 



0,00043 nearly by every degree between 60° and 70^, and 0,00034 nearly by every degree 

 between 49*^ and 60" , betv.-een 49° and 50° no difference was perceived. 



The Alterations of Denfity from Difference of Temperature In Nitrous yield, were as follow : 



Nitrous acid, which was 1,4279 at 60°, became 1,417831 70^;....!, 4225 at 65°;..., 1,4304 

 at 55" ;.... 1,4336 at 50"; and 1,4357 at 45°. — Hence nitrous acid, which at 60? is 1,4279, 

 gains or lofes o,ocioi nearly by every degree between 60° and 70° ; and 0,00052 by every 

 degree between 45° and 60". 



It was formerly found by Mr. Kirwan, that the ftrongeft fplrlt of nitre is moft expanded 

 by heat, or contraded by cold. Alfo, that nitrous acid, whofe fp. grav. at 34* was 1,4750, 

 was expanded by heat, as follows : viz. 1,4750 at 34° became 1,4653 at 49*^; whence it 

 gains or lofes 0,0097 by 15°, between 34° and 49'' inclufively. 



Again, that colourlefs nitrous acid, whofe fp. grav. was 1,4650 at 30", became 1,4587 at 

 46", and 1,4302 at 86". — Whence, by the firft 16S from 30' to 46'', it gained 0,0063, and 

 by 40*', that is, from 46 to 86", it gained 0,0285. 



Again, nitrous acid, whofe denfity was 1,2363 at 60', became 1,2320 at 70" ;.... 1,2342 

 at 65°;... 1,2384 at 55" ;.... 1,2406 at 50"; and 1,2417 at 45°. — Whence nitrous acid, 

 which at 60" is 1,2363, gains or lofes by every degree between 60° and 70° 0,00043, ^"'' 

 0,00036 by every degree betwen 60° and 45" ; and we may alTume o,«oc5 as the variation 

 incident to every degree between 60" and 70° in nitrous acid, whofe denfity at 60" is be- 

 tween 1,3 and 1,4, and 0,0004 for the variation between 44° and 60". 



Of Marine Acid. — It was formerly found that this acid of the denfity 1,196 at 33** be- 

 came of the denfity 1,1820 at 66*' ; the alterations of acids of lower fp. grav. were not exa- 

 mined ; but it was found that in general its dilatability is greater than that of nitrous acid of 

 the fame denfity. 



#* 



Tabi-b 



