536 



Proceedings of the Royal Physiccd Society. 



gets to this level no water can escape, as the upper chamber 

 is now air-tight. Only a small quantity escapes at a time, and 

 this is very rapidly boiled ; as it evaporates a small quantity 

 escapes to take its place, and so on. The reservoir holds 

 sufficient water to last for a couple of days, and steam can 

 be got up in under ten minutes. A much smaller steam 

 chamber suffices, and there is a great saving of both gas and- 

 time. 



The hot water funnel (Fig. 16) for filtering gelatine is made 



Fig. 16. 

 {a) Water jacket ; {b) enamelled fniinel ; (c) flask to receive filtered gelatine. 



like that in an ordinary hot water bath. It is simply a copper 

 or tin box (a) with two openings, around each of which is built 

 in a copper or tin funnel (6). Through these openings the 

 funnel stems project. This is much more convenient than the 

 ordinary hot water jacketed funnel. Instead of glass 

 funnels enamelled metal funnels are found to be good and 

 very economical substitutes. They are made of the ware 

 supplied by yacht outfitters. 



In order to do away with the troublesome method of filling 



