

HEINEMANN'S 



Scientific Ifoanbboofcs 



A KNOWLEDGE of the practical Sciences has now 

 become a necessity to every educated man. The de- 

 mands of life are so manifold, however, that of many 

 things one can acquire but a general and superficial 

 knowledge. Ahn and Ollendorff have been an easy 

 road to languages for many a struggling student ; 

 Hume and Green have taught us history; but little 

 has been done, thus far, to explain to the uninitiated 

 the most important discoveries and practical inventions 

 of the present day. Is it not important that we should 

 know how the precious metals can be tested as to their 

 value ; how the burning powers of fuel can be ascer- 

 tained ; what wonderful physical properties the various 

 gases possess ; and to what curious and powerful pur- 

 poses heat can be adapted 1 Ought we not to know 

 more of the practical application and the working 

 of that almost unfathomable mystery electricity ? 

 Should we not know how the relations of the Poles 

 to the magnet-needle are tested ; how we can ascer- 

 tain by special analysis what produce will grow in 

 particular soils, and what will not, and what artificial 

 means can be used to improve the produce ] 



