I v.— C H E M I S T E Y 



Art. LXI. — On the Preparation of Spo7itaneously Inflammable Phosphine. 



By T. A. MoLLET. 



[Read before the Philosophical Institute of Canterbury, 13th October, 1881.] 



Plate XXXVII., fig. 1. 

 Phosphueetted hydrogen, now generally known as phosphine, being one 

 of the gases commonly made for experimental purposes by the practical 

 student in the chemical laboratory, it is essential that the apparatus for 

 its production should be so contrived as to avoid all risk of an explosion. 



In the preparation of spontaneously inflammable phosphine it is usual 

 to employ a glass flask, fitted with delivery tube, to contain the alkaline 

 solution and phosphorus, from which the gas is generated. Before applying 

 heat to the flask a current of coal-gas is passed through, in order to displace 

 the contained air ; and the chief fault of the apparatus rests in the fact that, 

 unless this is continued for some time, it is impossible to expel all the air 

 from the vessel. Instead of using gas to displace the air, ether is sometimes 

 poured into the flask ; but this is open to the same objection, letting alone 

 the expensiveness of the liquid employed. 



Another and more satisfactory method of producing the gas is to gene- 

 rate it in a glass retort completely filled with the alkaline solution, the 

 mouth, of course, being immersed in the water of the pneumatic trough. 

 By this means we at once get rid of every particle of air, and all chance of 

 an explosion is done away with. There is, however, one fault to be found 

 with this form of generator. A considerable quantity of solution must be 

 used, and as most of this has to be heated to a high temperature, some delay 

 takes place before the required gas is given off. 



To avoid all these difiiculties I have designed a piece of apparatus which 

 is both simple and effective. An ordinary glass flask is taken and fitted 

 with cork and delivery tube ; but in addition to this, also passing through 

 the cork, is a deflagrating spoon, which should be so adjusted that the bowl 

 is about half an inch above the surface of the Hquid when in the flask 

 (pi. XXXVII., fig. 1). The pieces of phosphorus and the solution of caustic 

 potash (or other suitable alkaline hydrate) having been placed in the flask, 

 a small piece of dried phosphorus is put into the deflagrating spoon and 

 ignited. The flask is now corked and the oxygen, present as an objection- 

 able gas, combines with the phosphorus to form acids, which in no way 



