118 Canadian Record of Science. 



copyrite, 5*0 and 5*3 ; and for alabandite, 5*4. The smalt- 

 oids, niccolite and smaltite, give 4*4 and 5*1 ; the arseno- 

 pyritoids, cobaltite and gersdorffite, from 4*3 to 4*6; the 

 thiogaleaoids, for chalcocite, 7*0, for stibnite, 7'4, for galen- 

 ite, 7 - 9, and for argentite, 85. Of the sphaleroids, hauerite 

 gives 5-8 ; sphalerite, 6*0, and other species, 7 - 0-T4. The 

 contrasts between the last two tribes and the preceding 

 three, alike in their hardness, and in their condensation, as 

 shown in the different values of V, are apparent ; and these 

 are not less marked, when the hard and dense arsenopyrit- 

 oids are compared with the chemically analogous, but 

 softer, bournonoids and proustoids. Of the former of these, 

 enargite gives for V, 6*9, and bournonite, zinkenite and 

 jamesonite, T'T-T'S; while of the proustoids, miargyrite, 

 proustite, pyrargyrite and polybasite give from 8'0 to 9.0, 

 and dufrenoysite, and tetrahedrite, from 7'2 to 8*3. By 

 reason of the variations in the recorded specific gravities 

 of most of the species compared, the values here given for 

 V must be regarded as but approximations to be corrected 

 with the help of more exact determinations. 



The native compounds of the haloid elements may be 

 included under the order Haloidate, with the four subor- 

 ders of Fluorid, Chlorid, Bromid and Iodid. Titanates, nio- 

 bates, tantalates, tungstates, molybdates, chromates, vana- 

 dates, antimonates, arsenates, phosphates, nitrates, sul- 

 phates, borates, carbonates and oxalates constitute as many 

 distinct orders. Of these the soluble chlorids, sulphates, 

 borates, carbonates, etc., belonging to the salinoid type, 

 form tribes under their respective orders, as Chlorosalinoid, 

 Sulphatosalinoid, Borosalinoid and Carbosalinoid. The 

 native combustible carbons and hydrocarbonaceous bodies 

 are included in a single order, which, from the fire-making 

 property of these may be aptly designated as the order of 

 Pyricaustates. This is divided into two suborders: 1. Car- 

 bates, including the phylloid, graphite, and the adamantoid, 

 diamond, representing two tribes; and 2. Carbhydrates, 

 which may be conveniently grouped in the four tribes, 

 Naphthoid, Asphaltoid, Eesinoid and Anthracoid. 



Of these orders, Metallates, Haloidates and Pyricaustates 



