418 



THE GEOLOGIST. 



make a catalogue of fossils, induces nie to trouble you with a few lines on the 

 subject of a catalogue which I have nearly completed of my small collection of 

 minerals. 



I have arranged them according to the orders into which Professor Mohs 

 and Haidinger divide minerals, as given in Allan's "Mineralogy." 



Order. 



XT. Gem. 

 XII. Ore. 



XIII. Metal. 



XIV. Pyrites. 

 XV. Glance. 



XVI. Blende. 

 XVII. Sulphur. 

 XVIII. Eesin. 

 XIX. Coal. 



Order. 



I. Acid. 

 II. Salt. 



III. Haloide. 



IV. Baryte. 

 V. Kerate. 



VI. Zerene. 

 VII. Malachite. 

 VIII. Mica, 

 IX. Steatite. 

 X. Spar. 



I have also divided them into the chemical classes of 



1st, Earthy and alkalino-earthy minerals, 



2nd, Acidiferous minerals, 



3rd, Metallic minerals, 



4th, Combustible minerals, 

 by adding a column for this purpose to the catalogue. 



I enclose a specimen sheet, and shall be glad if it meets with your approval. 

 A few words on the subject of the principle upon which the above-mentioned 

 " orders" were institued would greatly oblige me. 



I may mention that I intend to mark each specimen with the number of the 

 order to which it belongs, and that the drawers containing the minerals in each 

 order are also numbered. As the subject may not be wlioUy uninteresting to 

 some others of your readers, perhaps at your leisure you will kindly favour us 

 witli a few more suggestions in a future number of your magazine, — I remain. 

 Sir, yours faithfully, A. B. M. W., Edinburgh. 



Order XI. 



Gem. 



Species Quartz 



Species Opal . . 



Name of Specimen, 



Rock Crystal 

 Cairngorum 

 Black Quartz 

 Quartz Crystals 

 Chalcedony 

 Flexible Sandstone 

 Heliotrope, or Blood-stone 

 Yellow Opal 



No. 



Class. 



Locality. 



1 



Earthy minerals 



Snowdon 



2 



ditto 



Arran 



3 



ditto 





4 



ditto 



Cheddar 



5 



ditto 



Lead-hills 



6 



ditto 



Thibet 



7 





Brun 



8 



ditto 



Mexico 



Order XII. 



Name of Specimen, 



No. 



Class. 



LocaUty. 



Ore. 



Specular Iron 



1 



Metallic minerals 



Elba 





Wood Tin 



2 



ditto 



Mexico 





Bro^vn Hematite 



3 



ditto 



Dover CUffs 



We recommend to our correspondent a copy of W. Phillips' "Mineralogy" 

 (any edition before the one by Brooke and Miller, especially the 4th), and 

 to arrange her collection in the order that Phillips' adopted and uses in his book. 

 It is the most practicable for general purposes. 



Elliott's Clinometers. — Siu, — Some time ago vou promised to give an 

 account of instruments in use by geologists. Will it be convenient, in the 

 absence of this, to afford me some explanation of the two scales of the clino- 

 meter made for geologists by Elliott Brothers, Strand. The principal gradu- 

 ation on the brass arc is intelligible, being the quadrant divided into ninety 

 degrees ; but the arc contains an inner line 1 | 1, I | 2, 2, 3, &c. Query. 



