Vlll 



perhaps entertain a hope of being able at a future 

 period to atone in some measure for this deficiency, 

 At present I shall be satisfied if the work, now of- 

 fered to the public, should prove an auxiliary to 

 the study of an interesting science, and be satisfac- 

 tory to those friends who have obligingly aided me 

 with facilities during its composition. I flatter my- 

 self that among its faults, the most numerous will 

 not be its errors ; and whatever may be its fate 

 with the public, I shall retain the consciousness, 

 that it has not been the result of superficial inquiry, 

 or negligent observation. 



Boston, May, 



