1818.] the Commencement of the Year 1817. Part l. 27 



(4.) Corrosive sublimate does not seem to absorb ammoniacal 

 gas. Calomel absorbs it more rapidly. Chloride of lead and 

 chloride of bismuth exert but little action. 



(5.) Chloride of copper absorbs ammoniacal gas copiously, 

 and falls into a blue powder. 



(6.) Protochloride of iron absorbs a great quantity of ammo- 

 niacal gas, and is converted into a very light, adhesive, white 

 powder. When exposed to the air, it immediately changes 

 colour, becoming yellow, brown, then green, and ultimately 

 black. This is owing to the absorption of aqueous vapour; of 

 the presence of which it constitutes a very delicate test. — (Royal 

 Institution Journal, v. 74.) 



6. Soaps. — M. Chevruel has shown that all oils are divisible 

 into two portions ; one portion, usually solid, he calls stearine ; 

 the other, usually liquid, he calls elaine. Both of these oily 

 bodies unite with alkalies in definite proportions, and are con- 

 verted by the union into substances having acid qualities, which 

 he has distinguished by the names of margaric acid and oleic 

 acid. The equivalent number of margaric acid is 33, while that 

 of oleic acid is 36. 



Some valuable experiments on soap-making have been pub- 

 lished, by M. Colin, in the Annales de Chimie et Physique, 

 iii. 1. They are not of such a nature as to admit of abridgment; 

 but they are well entitled to the attention of the practical soap- 

 maker, who might, perhaps, acquire ideas from their perusal 

 that would enable him to ameliorate some of his processes. 



7. Since the original paper on Morphia, by Serturner, of 

 which an abstract was published in the Annals of Philosophy 

 more than a year ago, several papers on the same subject have 

 appeared, an account of which will be given hereafter. 



IX. SALTS. 



1. Property of certain Salts to give their crystalline Form to a 

 much larger Proportion of other Salts. — M. Beudant has made 

 an important set of experiments on this subject, which is inte- 

 resting chiefly by showing us that the real mineral species which 

 give the form may be fixed with a very great proportion of other 

 substances, without any alteration in the crystalline form being 

 induced. M. Beudant found that when two different salts were 

 mixed together in certain proportions, and the solutions were 

 crystallized, the crystals obtained never contained the two salts 

 in the same proportions that had been originally mixed, but in 

 some other proportion, lie found that crystals might be obtained 

 composed of 85 parts of sulphate of zinc and 15 parts of sulphate 

 of iron, of 91 parts of sulphate of copper and 9 parts of sulphate 

 of iron; and of 72-75 parts of sulphate of copper. 24-25 parts of 

 -ulphate of zinc and 3 parts of sulphate of iron ; and yet all of 

 these crystals have the form of the crystal which distinguishes 

 sulphate of iron. — (Ann. de Chim. et de Phys. in. 281; and 

 Annals of Philosophy, ix. 262.) 



