CHEMISTRY. 519 



Presence of lellurium in Copper. — Prof. Th. Egleston has detected 

 tellurium iu commercial copper to the extent of about 0.1 per cent. A 

 surprisingly small quantity renders the copper red-short, and conse- 

 quently -worthless for rolling. ( Trans. Am. Inst. Mining Engineers^ Har- 

 risburg Meeting, Oct., 1882.) 



Complex inorganic Acids. — Dr. Wolcott Gibbs has published a con- 

 tinuation of his remarkable researches on the complex inorganic acids. 

 He has demonstrated that inorganic compounds possess an unexpected 

 degree of complexity, and has entered a very wide field of research, yield- 

 ing a rich harvest. After discussing in detail several phospho-molyb- 

 dates, he describes the preparation of the arsenio-molybdate having the 

 composition: 



10 MoOg. AS2O5. 5 (NH,).i O. H2O -f 8 aq. 



The study of these two series (pbospho- and arsenio-molybdates) 

 leads to the following general results: 



1. The phosi)homolybdates form a series of which the lowest term 

 contains five atoms of molybdic to one of phosi)horic oxide, and the 

 highest twenty-four atoms of the former to one of the latter. 



2. As in the case of the phospho-tungstates, the greater number of 

 the molybdenum compounds contain an even number of atoms of tung- 

 stic acid. The homologizing term is, therefore, 2 M0O3 for these cases. 



3. By far the great*^r number of phospho-molybdates contain three 

 atoms of fixed base (old style), or, in more modern language, may be 

 considered as derived from acids containing six atoms of hydroxyl. 

 Anhydrous compounds of this type occur, and are not always simply 

 residues obtained by heating salts which may be considered as acid, as 

 containing, for example, 3 E2O. 3 n20. It seems, therefore, necessary 

 to admit the existence of acide of the general type n M0O3. P2O5. 3 H2O. 



4. On the other hand, while no single phosphomolybdate containing 

 more than three atoms of fixed base for one of phosphoric oxide has^ 

 been obtained in a state of indubitable purity, there is i^robably at least 

 one salt with six or more atoms of fixed base, viz : 



22 M0O3. P2O5. 7 Ag20 + 14 aq. 



5. Negative evidence concerning the probable non-existence of a 

 series of phospho- or arsenio-molybdates containing more than three 

 atoms of fixed base, must not be too highly regarded. 



6. As in the case of the phospho-tungstates, there exists a class of 

 phospho-molybdates in which the ratio of the number of atoms of base 

 to that of the number of atoms of phosphoric oxide is as 5 : 2, the num- 

 ber of atoms of molybdic oxide being even. 



Dr. Gibbs jjresents a series of structural formulae which explain all 

 degrees of basicity which appear to be possible under the general con- 

 ditions of the problem. For these and other details we refer to his origi- 

 nal paper. {Am. Chem. J., iii, p. 402.) 



