PREFACE. 



SINCE the publication of the former edition of this Manual, 

 Steele's Physics and Chemistry have been thoroughly revised, 

 and the Hygienic Physiology has been published. The present 

 issue has been prepared to accompany these later editions, and 

 includes complete reference to all the problems and practical 

 questions contained in Steele's Popular Physics, Popular Chemis- 

 try, Hygienic Physiology, and New Descriptive Astronomy. 

 Great pains have been taken to revise and compare the prob- 

 lems, which are fully, and, it is thought, accurately solved. 

 The practical questions, as in the former edition of the Manual, 

 are often not answered in full, yet sufficiently so to furnish a 

 key to the more perfect reply. The use of the text-books is 

 presupposed, and the statements merely supplement, or apply 

 the theories therein contained and explained. Upon many points 

 there may be, and often is, a difference of opinion. On these 

 mooted questions only that view which appeared to the author 

 to have preponderance of argument has been advanced, leaving 

 the subject open for the discussion of other theories. 



The former edition of the Manual can still be obtained by 

 those teachers who continue to use the earlier editions of the 

 Sciences, although, with a few exceptions, the problems and 

 questions therein answered are incorporated with those which 

 have been added in the present issue. 



DECEMBER, 1888. 



163 



