630 KEPORT— 1888. 



cadmium and arsenic, and the singular metallic character assumed by the complex 

 tungstates or Tungstometalloids, known as tungsten bronzes. These, with the not 

 less remarkably complex soluble tungstates or Tungstosalinoids, and the native 

 tungstic species, make the Tungstates one of the most instructive orders known. 



§ G. The author has elsewhere proposed to divide the mineral kingdom into four 

 classes, including (1) Metalline, (2) O.xydised, (8) Haloid, (4) Pyricaustate (com- 

 bustible or fire-making) species. Each of these classes is again divided into orders, 

 tribes, genera and species. In the first class a single order includes two sub-orders 

 and nine tribes, named (1) Metalloidese ; (2) Galenoidete, including three sub-tribes 

 corresponding to sulphur, selenium and tellurium compounds; (3) Bournonoidese ; 

 (4) Pyritoideae ; (5) Smaltoidese ; (6) Arsenopyritoidese ; (7) Spatometalloidete ; 

 (8) SphaleroidesB ; (9) Proustoidese ; each tribe including one or more genera. 

 Again, in the second class are grouped under different orders, Oxyds, Silicates, 

 Carbonates, Borates, Sulphates, Phosphates, Tungstates, &c. Three sub-orders of 

 silicates include protoxyd, protoperoxyd and peroxyd silicates ; among peroxyd 

 bases being reckoned alumiuic, ferric, manganic, chromic, bismuthic, and also, for 

 special reasons, zirconic oxyd. Recognising in each sub-order various types desig- 

 nated Hydrospathoid, Spathoid, Adamantoid or gem-like, Phylloid or micaceous, 

 and Porodic or colloidal ; the tribes may be named Pectolitoid, Willemoid, Am- 



Jhiboloid, Talcoid, Ophitoid, Zeolitoid, Feldspathoid, Granatoid (garnet-like) 

 [icoid, Pinitoid, Perzeolitoid, Eulytoid, Topazoid, Pyrophylloid and Argilloid. 

 Soluble saline species in any order are referred to a salinoid type, as Borosalinoid, 

 Tungstosalinoid. The extension of this system to the Haloid and Pj'ricaustat* 

 classes is easy, and has been elsewhere explained. 



The work of arranging in genera and species, with a Latin binomial nomencla- 

 ture, and the determination for each species of the value of v, is now nearly 

 completed for the first two classes ; and the whole will probably soon appear, with 

 a proper introduction, as a Systematic Mineralogy, to be followed by a Descriptive 

 Mineralogy. The general principles here set forth are discussed at length in the 

 author's 'Mineral Physiology and Physiography' (Boston, 1886), pp. 279-401, 

 where, in a chapter entitled ' A Natural System in Mineralogy,' will be found an 

 examination of the constitution and relations of the known natural silicates 

 arranged in tribes, and tabulated, with the calculated values of v, and a new quan- 

 tivalent chemical notation. See further, a paper on ' The Classification and Nomen- 

 clature of Metalline Minerals,' ' discussing Class I., in the ' Proceedings of the 

 American Philosophical Society' for May 4, 1888, reprinted in the ' ('hemical 

 News 'of August 10 and 17; also the author's 'New Basis for Chemistry,' 2nd 

 edition (Boston, 3888), where, in chapters vii. and xiv. many points in the 

 proposed mineralogical classification are elucidated. 



6. Oil the Logarithmic Lmv mid its Connection witli the Atomic Weights. 

 By Dr. G. Johnstone Stoney, F.B.S. 



7. On Dissociation? By the Rev. A. Irving, D.Sc, B.A. 



The author refers to the paper on this subject which he read before Section B 

 at the Birmiugham meeting in 188G. Further work has furnished confirmatory 

 evidence in support of the theory then propounded. From a number of experiments 

 recently made, visible evidence has been obtained of the direct dissociation of the 

 hydrocarbons of coal-gas. The deposition of amorphous carbon takes place in 

 contact with pumice-fragments at temperatures ranging from dull red heat up to 

 the incipient fusion-temperature of the hardest Bohemian glass. Along with 

 carbon some sulphur is also deposited. We have thus a visible confirmation of 



' An abstract of this paper, printed in the progTamme of the Royal Society of 

 Canada, without revision or correction by the author, will also be found in the Chemical 

 Mivs for June 29, 1888. 



' Tublished in extenso in the Chemical Neiis, No. 1505, September 28, 1888. 



