PEEFACE, 



THE present book is intended as a guide to the understanding 

 of our popular scientific literature. Among the multitude of 

 technical terms that are in existence, a selection had to be 

 made, and the reader will therefore not expect absolute 

 completeness, which, if possible, would have greatly increased 

 the bulk, and thereby have impaired its convenience for 

 ready use. Only the most commonly used, and most im- 

 portant words have accordingly been included. At the same 

 time, accuracy with brevity has been specially aimed at. The 

 fact that it has been found possible to include about 14,000 

 entries is the best evidence of the range and conciseness of tho 

 following pages. 



August, 1878. 



