i v PREFACE. 



The necessity of the pupils copying (however poorly) the 

 figures, either upon the slate, or upon paper, cannot be too 

 strongly urged. 



From his own experience, the author has learned that a 

 specimen or figure may oftentimes be carefully studied, and 

 yet only an imperfect idea be formed of it ; but, when it 

 had been once copied, the new points gained repaid all the 

 trouble spent in the task. 



It makes but little difference whether the pupil is profi- 

 cient in drawing or not ; it should be strenuously insisted 

 upon by the teacher that the pupils copy, as far as possible, 

 the figures contained in each lesson. 



To collect in the field, to make a cabinet, and then to ex- 

 amine and study the specimens collected, are the three stages 

 that naturalists, with few exceptions, have passed through in 

 their boyhood. 



If one recalls the way in which boys first manifest their 

 taste for such studies, he will remember that first a few ex- 

 amples were brought together ; a collection was made. It 

 may have been birds' -eggs, insects, or shells; then little 

 boxes, a case of drawers, or shelves, were secured to hold 

 their treasures. In thus collecting and arranging and rear- 

 ranging the cabinet, the eye becomes familiar with the out- 

 line and general character of the objects, and in this way the 

 mind is finally prepared to comprehend the relations existing 



