PREFACE, 



THE present number completes the fourth yearly vol- 

 ume of the Annual of Scientific Discovery. In its 

 preparation, the Editor has followed the general plan 

 indicated and developed in the former numbers of 

 the work. 



The mental activity at present displayed in developing 

 new principles and modifying old ones, to meet the 

 wants of practical industry, in cheapening and improving 

 the production and preparation of all raw materials, and 

 disseminating useful knowledge, is probably greater than 

 at any former period of the world's history. Under 

 these circumstances, the labor of preparing an annual 

 retrospect has been greatly increased. The Editor has, 

 however, endeavored to present as faithful an abstract 

 of the progress of science and the useful arts during 

 the year eighteen hundred and fifty -two, as the limits 

 of the present volume would allow. The field for 



