336 On some Comlinatimis of Plalhiuin. 



nected vvitli tlie decomposition of both substances. When tiifi 

 powder is broii^lit in contact with the vapour of alcohol, at the 

 common temperature of the air, there is an immediate chemical 

 action; tlie heat generated is sufficient to reduce and ignite the 

 metal, and to continue it in a state of ignition, until the alcohol 

 is consumed. In this case, the acid first noticed by Sir H. Davy 

 (in his beautiful experiment of the iiijnired platinum wire, and 

 since, more fully examined by I\Ir. Daniell) is produced. In 

 either instances, the acetic acid, as has been mentioned, is formed. 

 It would be premature to speculate on the uses to which this pow- 

 der may be applied; but, froni its peculiar properties, there is rea- 

 son to think it will admit of some useful applications. I have 

 already employed it as an easy means of affording heat and light. 

 To produce heat, it is onlv necessary to moisten any porous sub- 

 stance, such as sponge, cork, cotton, asbestos, sand, &;c. with 

 alcohol or whiskey, and to let a particle of the powder fall on 

 the substance so moistened ; it instantly becomes red hot, and 

 remains so until the spirit is consumed ; nor is the ignited metal 

 extinguished by exposure to the atmosphere, or by blowing the 

 breath on it; on the contrary, pintial currents of air only make 

 it glow brighter. The heat produced in this way may be accu- 

 mulated to a considerable extent, by increasing the quantity of 

 the materials employed. I have also constructed a tinder-box, 

 to procure immediate light by n)eans of the powder. It consists 

 of two small phials placed in a japanned box, and some sulphur 

 matches tipped with phosphorub. One of the phials contains 

 the powder; the other, alcohol. The stopper of the phial con- 

 taining the alcohol, has a bit of sponge inserted in a small aper- 

 ture at the bottom of it. When a light is wanted, it is only ne- 

 cessary to shake the bottle so as to moisten the sponge with the 

 alcohol, take out the stopper, and put the smallest particle of 

 the powder on the moistened sponge ; it instantly becomes red 

 hot, and will readily kindle one of the matches. This mode of 

 igniting a metal seems to be quite a new fact in the history of 

 chemistry; but the means of keeping it in a state of ignition is 

 only another illustration of the facts previously pointed out by 

 Sir H. Davy in his late valuable researches, which have thrown 

 so much light on the philosophy of flame, and led to such very 

 interesting, important, and unexpected results. 



5. On the Effects of Sulphate of Platinum upon Gelatine. 



When an aqueous solution of sulphate of platinum is added to 

 any solution of gelatine, such at, isinglass, size, or glue, a preci- 

 pitate occurs, and all the sulphate is separated in union with the 

 gelatine; or, if a minute portion remain, it is precipitated on 

 boiling the fluid. This precipitate, whilst in a moist state, is of 



a brown 



