The mode of sub-divuliu,i>- entries made iiader any element in 

 each numbered division shall be as follows: — 



(a) All entries relating- either to the elem3nt itself or of a 



general character shall come immediately under the 

 number. 



(b) Salts are to be in lexed un ler the registration number of 



the metal, and, in grtnoral, compounds are t) be 

 indexed under the registration number of the most 

 characteristic element in them. 



The registration number must ba immediately followed 

 by the symbol of the characteristic element, followed 

 by that of the other element or elements. Whei-e one 

 compound only is dealt with, its formula may be given 

 immediately after the registration number. 



Thus, after each metal, its compounds with the following 

 elements would be placed in the following order in the 

 Catalogue : As, B, Bv, C, CI, F, H. I, X, 0, P, S, Si, 

 these, and any other elements being taken in the 

 order in which they occur in the preceding table. 



(c) References to hydroxides, acids, and salts that contain 



oxygen shall be entered under the oxide ; the corre- 

 sponding sulphur compounds under the sulphide. 



Thus, under 0i20 KO would be placed the following 

 compounds of potassium (among others) : oxides, 

 hydroxide, nitrate, nitrite, hypophosphite, phosphate, 

 hypochlorite, hypobromite, chlorite, chlorate, per- 

 chlorate, bromalo, iodate, sulphite, sulphate, silicate, 

 manganate. pernianganate, &c. 



Under 0420 KS would be placed any compound containing 

 sulphur that may be considered to be derived by the 

 substhution of sulphur for one or more atoms of 

 oxygen, e.<j., sulphide, sulph-hydrides, thiocarbonates, 

 dithiocarbonates, trithioearbonates, thiosulphates, 

 thionates. thioarsenites, &c. 



(</) In each subdivision the entries may be arranged in such 

 order that those relating, «, to the history- or origin of 

 the substance come first, and following these, those 

 relating, /i, to its physical properties ; 7. to its pre- 

 paration or manufacture ; f, to its structure, or of a 

 theoretical nature; e, to its interactions or use; i*, to 

 its compounds. 



It will, as a rule, be unnecessary to repeat a reference to any 

 one substance under each of the sub-sections, n—t; ; it would sulhce 

 to enter the reference in one of these (say /:?), and to ap()end at 

 the close of the entry, 7, c, &c., if statements of special impor- 

 tance falling under these headings are made in the conmiunica 

 tiou. 



(D-3182) B 2 



