34 THE MICROSCOPE. 



that in order to facilitate the advancement of all the branches of 

 useful science, two things seem to be chiefly necessary. The first 

 is an historical account of their rise, progress and present state; and 

 the second, an easy channel of communication for all new dis- 

 coveries. Without the former of these helps, a person every way 

 qualified for extending the bounds of science, labors under great 

 disadvantages; wanting the lights which have been struck out by 

 others, and perpetually running the risk of losing his labor and 

 finding himself anticipated in the discoveries he makes, which is a 

 great mortification and discouragement. In other respects, also, 

 the progress of natural knowledge is retarded on this account; so 

 that in the present state of science such histories as these are in a 

 manner absolutely necessary. 



''Considering how very few persons are acquainted with the 

 present bounds of any branch of science, or, indeed, are in circum- 

 stances in which it is possible for them to acquire that knowledge, 

 and how much time and labor are even, in that case, necessary in 

 order to acquire it, it must be allowed that were these histories 

 judiciously compiled real discoveries would be much more numer- 

 ous; and were these again easily and expeditiously circulated the 

 progress of knowledge might be accellerated beyond what we now 

 can conceive.'" 



Our numerous and valuable scientific and popular-science journals 

 afford the "easy channel" much longed for by Priestley. But no 

 one from his day (1772) until Queckett's time (1848) attempted to 

 continue the good word so ably begun by the renowned Priestley. 

 Even in the works of to-day if any reference whatever is made to the 

 history of the instrument it is of the most cursory character and 

 then filled with inaccuracies. It shall by my endeavor therefore as 

 far as lies in my power to confine myself to extracts from the 

 original authors. Even so careful an historian as Dr. Priestley I 

 will discard when the originals from which he compiled are attain- 

 able. 



I am persuaded too that ere we finish our studies of this subject 

 my readers will, with me, be ready to endorse the proposition for- 

 mulated by Aristotle over two thousand years ago that "probably all 

 art and all wisdom have often been already explained and again 

 quite forgotten." 



I Priestley's "History of Optics." 



