PREFACE. 



The following technical methods, arranged as simply 

 and concisely as possible, are especially intended for con- 

 venience in laboratory work. One constantly wishes and 

 uses the methods herein enumerated, and for the same 

 must refer to the large text-books. It is to avoid this 

 longer search, except for details, that the following scheme 

 is published — a scheme which the writer adopted some 

 years ago for his own convenience, and which he sincerely 

 hopes others may also find a useful desk companion. 

 Before describing the different methods, there are men- 

 tioned a few ways by which the work may be much 

 accelerated — ways probably known to and practised by 

 many, but not, perhaps, to all. 



