230 



Domestic Science 



does any creation of new matter take place ? " To 

 answer this question, the balance is again brought into 

 use, but this time the whole of the apparatus is weighed. 



EXPERIMENT 91. Cut off under water a small piece 

 of yellow phosphorus. Remove it from the water, and 

 dry it carefully with filter-paper. Drop it gently into 

 a stout round-bottomed flask, 

 or bolthead, F, of from 1-5 to 

 2 litres capacity. Push in a 

 tight -fitting rubber stopper, R, 

 and wire the stopper in firmly 

 with copper wire. Weigh the 

 flask and its contents carefully. 



Holding the neck with a 

 duster, bring the part of the 

 flask where the phosphorus is, 

 into a small Bunsen flame. 

 The flask should be held at 

 arm's length with the neck 

 pointing toward the experi- 

 menter. As soon as the 

 phosphorus ignites, withdraw the flask from the 

 flame, and hold it steadily away from the body till the 

 phosphorus ceases burning. Allow the flask to cool 

 down, and when it has regained the temperature of 

 the room, weigh it carefully. It will be found that 

 its weight is unaltered. 



(Note. The flask may burst on account of the in- 

 creased internal pressure due to the rise of temperature 

 produced by the burning of the phosphorus, but no 

 damage will follow such an occurrence if the operation 

 be carried out exactly as described.) 



Thus, although some or, it may be, all of the phos- 

 phorus has disappeared, and an entirely new body, the 



