1820.] Mr. Dalton on Sulphuric Ether. 125 



Manometer. Measures of ether 



evaporated. 



March 5 9 a. m 3885 27-0 



6 9 3874 28-0 



9 p.m 3874 28-0 + 



7 9 a. m 3874 28*0 + 



For the last two days there was only a drop of fluid left at the 

 bottom of the tube (nearly five inches deep) which seemed to be 

 not evaporable ; but it was judged proper to continue the expe- 

 riment in order to ascertain whether the vessel was perfectly air 

 tight, aiid of course the gauge would continue stationary. The 

 drop of fluid smelled of alcohol, and when diluted and treated 

 with muriate of barytes was milky. 



By making the calculation as above, the specific gravity of 

 ether vapour from the first part of the experiment comes out 

 3-05, and from the last part, 3-2. The slow manner in which 

 ether evaporates in these circumstances is surprisinr»- ; in the 

 latter part of the experiment it is to be ascribed to the depth of 

 the surface of fluid in the tube, and the partly saturated air. 



Though convinced the above results were very good approxi- 

 mations, I was desirous to have a confirmation of it by some 

 more direct method. I took a bottle of the capacity of 2,600 

 gr. of water, and graduated accordingly ; this being tilled up to 

 1,100 gr. with dry mercury was inverted in the mercurial trough 

 with 1,500 common air. Through this mercury were passed 1, 2, 3, 

 or more grains of ether, which expanded the air, and from the 

 quantity of expansion, compared with the weight of ether let up, 

 the specific gravity of the vapour was inferred. This method 

 did not give uniform results owing to a considerable portion of 

 such minute quantities of ether being entangled by the mercury 

 in its passage. To remedy this, I took a small tube, one-seventh 

 of an inch in diameter internally, and two inches long, which 

 was sealed at one enil, and then graduated into water grains, 

 which was such as to allow nearly one-fourth of an inch for one 

 grain. This was filled with mercury, except for one, two, or 

 more grain measures, which were afterwards filled with ether,, 

 and the finger being apphed, the tube was plunged into the 

 mercury and passed through the neck of the bottle up to the 

 surface of the mercury in the bottle. In this way the ether was 

 conveyed through the mercury without quitting the tube, and by 

 gentle agitation was ejected and dissipated in vapour in a few 

 minutes afterwards. The results in several experiments were 

 nearly uniform, giving an increase of volume of gas from 255 to 

 275 grain measures for each grain of ether in vveiglit. This 

 gives the specific gravity of ether vapour from 3-1 to 3*3. On 

 the whole, I think 3- 1 is probably the nearest exoression in two 

 places of figures that can be attained. 



