192 THE FLOATJNG-MATTEE OF THE AIR. 



iced water, witli tlie view of rendering the air within 

 the bulb denser than that without. The pinchcock p 

 being closed, the whole apparatus was then detached 

 from the air-pump. On being lifted from the iced 

 water into the warmer air there was a gentle outflow of 

 air from a. 



The mode of charging the bulb was this : — The point 

 a was well sunk into the infusion, and the associated 

 bulb, B, was plunged into boiling water. There was an 

 immediate outrush of air from a which bubbled through 

 the liquid. As soon as the bubbling had relaxed a 

 little, a being still submerged, the bulb was transferred 

 to iced water. A shrinking of the warm air was the 

 consequence, and through a the infusion was forced by 

 atmospheric pressure. It descended the middle branch 

 of the "f-tube, and was discharged from its end e into 

 the bulb. The quantity of liquid obtained by a first 

 immersion in the iced water was not suflScient to charge 

 the bulb; but by repeating the process of heating and 

 chilling two or three times, the point a never being 

 permitted to quit the infusion, any required quantity 

 was with ease and accuracy introduced. The neck of 

 the bulb was finally detached from the J-piece by 

 loosening the india-rubber tube. The bulb was then 

 slightly warmed so as to cause an outflow of air from 

 within, and while this outflow continued the neck was 

 plugged with cotton-wool. It was sealed above the 

 plug, and after the cooling of the infusion the sealed 

 end was broken off with a file. 



It is not my intention to take up time in 

 describing in detail the numerous experiments made 

 in accordance with this method, or the variety of 

 infusions employed in testing its efficacy. Suffice 

 it to say that, notwithstanding all my care, the 

 results were chequered throughout. Sometimes success 



