IDG Description and Analysis of the [Sept, 



means of water and muriatic acid, and then evaporated the solution 

 to dryness. From this dry mass the lime and alumina were dis- 

 solved by means of muriatic acid boiled upon the powder. The 

 acid solution being mixed with a great excess of caustic potash, the 

 lime was thrown down and separated by the filter. The alumina 

 was then separated by means of sal ammoniac, and likewise col- 

 lected on the filter. By dividing the loss which in working upon 

 such small quantities is unavoidable, we may estimate the T848 

 gramme of ignited powder to consist of I '6905 gramme (26 108 

 grains) of silica, 0-0825 gramme (0-139/ grain) of alumina, and 

 0-0/5 gramme (0-1 15S grain) of lime. 



It is obvious from this that hauyne cannot be accurately analysed 

 by means of muriatic acid ; as it is always to be feared that the 

 silica separated by its means retains a portion of the other earths, 

 and even of the potash. 



g. — The liquid separated from the powder in paragraph c was 

 limpid. It was evaporated in a glass capsule till it deposited needle- 

 form crystals, and assumed a yellow colour. It was then gradually 

 reduced into a yellow pulverulent mass, which rapidly absorbed 

 moisture from the atmosphere. 



h. — This dry mass was repeatedly boiled in different portions of 

 the pure alcohol of Richter, which were successively decanted off 

 and poured upon the filter. 



i. — The powder remaining upon the filter, being edulcorated with 

 a sufficient quantity of hot alcohol, was white ; and being dried 

 upon the sand-bath, weighed 2-330 grammes (35-985 grains). Of 

 this 1*618 gramme, being ignited for half an hour, melted into a 

 dirty white mass, which was a little swelled, and weighed 1-496 

 gramme. As this diminution of the weight appeared too small on 

 the supposition that the greatest part of the mass consisted of sul- 

 phate of lime, it was exposed for half an hour longer to a still 

 stronger heat, by which the weight was reduced to 1*336 gramme. 

 It had been again melted, and the colour was become more dirty 

 than before. As this mass, as we shall see immediately, contained 

 a good deal of muriate of lime, there is reason to suspect that a 

 portion of this salt was volatilized by this repeated exposure to so 

 high a temperature. 



k. — Water was boiled on the portion of the powder of paragraph t 

 that had not been exposed to a red heat. This liquid, after filtra- 

 tion, precipitated in abundance sulphate of silver, and was not 

 rendered turbid by caustic ammonia. The carbonate of ammonia 

 precipitated white flocks from the hot solution. The fluid separated 

 from these being evaporated, formed a granular precipitate, with a 

 solution of platinum. 



/. — The presence of muriate of potash in the powder being thus 

 recognised, the ignited portion of the powder (/), weighing 1*836 

 grammes, was treated with a sufficient quantity of water. This 

 liquid being filtered and evaporated, yielded «at first needle-form 

 crystals ; which being edulcorated with some water, and afterward* 



