XX INTRODUCTIO:S. 



The following is a list of metals arranged ia the order of their magnetic 

 powers, as approximatively determined by Faraday: — Iron, Nickel, Cobalt, 

 Manganese, Chromium, Cerium, Titanium, Palladium, Platinum, Osmium — 

 to which, may be added Aluminium. 



Chemical Composition. 



Mineralogy is daily becoming a science more and more based on Chemistry; 

 as it is only by means of the chemical analysis of minerals that we can arrive 

 at a true knowledge of their composition ; — that is to say, of the simple 

 substances of which they are composed, and of the manner in which those 

 substances are combined. 



It is quite beyond the scope of a work of this kind to do more than allude 

 to the subject, except so far as to point out that the blowpipe offers a simple 

 and ready means of testing minerals, and of determining the species to which 

 they belong. 



For the way of using this useful little instrument, the student may consult, 

 with advantage, several treatises- A brief, but extremely clear and well- 

 written notice of the mode of using the blowpipe, by Mr. Warlngton 

 Smyth, Professor of Mineralogy and Mining in the Government School of 

 Mines, is contained at p. 259 of the Manual of Scientific Inquiry, published 

 by the Lords of the Admiralty. This notice is drawn up in so comprehensive 

 and masterly a manner that it has been introduced here (by the kind 

 permission of Mr. Smyth, who has allowed it to be made use of). 



"The ordinary blowpipe is so well known as scarcely to need description. 

 Various forms have been recommended by their inventors, but for common 



purposes it is only important that the orifice be not too large, and that the 

 tube be provided with a reservoir for the reception of the moisture which is 

 carried into it with the breath. The flame of a neatly-trimmed lamp is, 

 undoubtedly, the most convenient, but that of a common candle is quite 

 applicable to the qualitative tests with which we shall have occasion to deal. 

 "In looking at the flame of a candle, we may observe two principal 

 divisions which it is necessary by the assistance of the blowpipe to use 

 separately, since their action on the same substances is so different, as, on 

 the one hand, greatly to facilitate certain processes of analysis, and, on the 

 other, to cause much perplexity unless clearly understood. 



