hitelligence and Miscellaneous Articles. 315 



According to these statements, it will not be surprising to observe 

 antimony and arsenic subject to the common law, and belong to the 

 regular system, which appears really to be that of all the metals. — 

 Ann. de Ch. et de Phys., Janvier 1 848. 



ON THE CRYSTALLIZED MONOHYDRATE OF ZINC. 

 BY M. J. NICKLeS. 



The author states that a mineral exists, and is known by the name 

 of cupreous hydrate of zinc, which contciins the hydrates of zinc and 

 copper, and has the cleavages of a right rhombic prism ; and wishing 

 to know the relation it might bear to the artificial monohydrate of 

 zinc, he prepared some of it to examine its crystalline form. 



Runge was the first who observed the formation of crystallized 

 hydrate of zinc on a pile, the elements of which, iron and zinc, were 

 immersed in ammonia, potash or soda. Schindler found it to con- 

 sist of — 



Oxide of zinc 81-62 



Water 18-36 



These numbers agree with calculation, which requires 81-71 of 

 oxide and 1 8-29 water. Two experiments gave M. Nickles the same 

 number. 



The process recommended by M. Runge is very simple. It is 

 sufficient to introduce iron and zinc into a bottle containing either 

 potash or ammonia ; after some time, small crystals of the monohy- 

 drate are deposited on the sides of the bottle ; very pure hydrogen 

 gas is given out during the action. 



This hydrate has the form of very limpid right rhombic prisms. 

 When prepared from the zinc of commerce, these crystals frequently 

 contain a black nucleus derived from the impurity of the zinc. This 

 nucleus diminishes their limpidity, but renders the faces more re- 

 flective. The crystals are generally modified in the same manner. The 

 summit is terminated by a bevil parallel to the great horizontal axis, 

 and the lateral edges are generally truncated by a terminal face. It 

 will be observed that these crystals belong to the same system as the 

 hydrate of zinc and copper of mineralogists. 



The author states that some observations were made by him during 

 the preparation of the crystals, which he transcribes : the laminated 

 zinc of commerce is more readily attacked than the fused metal : 

 some of the latter was introduced into ammonia, with another por- 

 tion of the same zinc laminated ; the laminated zinc was dissolved 

 in a short time, but the fused metal was hardly acted upon. When 

 it is recollected that laminated zinc is denser than fused, the differ- 

 ence of solubiUty appears singular ; but it is readily explained by 

 considering the texture of both. In fact, when fused and cooled, 

 zinc has a crystalline structure, which it loses completely by lamina- 

 ting ; and it is well-known, that in general crystallized substances 

 do not so readily dissolve as amorphous bodies. 



The state of the iron employed also influences the energy of the 

 reaction ; but in this case it is the less dense metal which acts the 

 best. Iron turnings favour the reaction, but laminated or forged 



