4 LECTURE I. 



verbally professed, to bring down philosophy from the heavens, and to make 

 her an inhabitant of the earth. 



To those who are engaged in the practical cultivation of various arts, sub- 

 servient to the conveniences of life, these lectures may be of some utility, by 

 furnishing them with well established principles, applicable to a variety of 

 cases, which may occasionally occur to them, where a little deviation from the 

 ordinary routine of their profession may be necessary. Unfortunately, the 

 hands that execute are too often inadequately supported by the head that dir 

 rects ; and much labour is lost for want of a little previous application tp the 

 fundamental doctrines of the mechanical sciences. Npr is any exorbitant 

 portion of time or industry necessary for this purpose; for it happens singu- 

 larly enough, that almost all practical applications of science depend on prin- 

 ciples easily learnt; and, except in astronomy only, it has seldom been fbund 

 that very abstruse investigations have been of great importance to society. 

 Our most refined analytical calculations are by far too imperfect to apply 1;o 

 all possible cases of mechanical actions that caabe proposed; ai^d those pro- 

 blems which most frequently occur, may in general be solved by metliods 

 sufficiently obvious ; although, from a want of proper order and perspicuity 

 in the treatment of first principles, it has often happened that the most ele- 

 mentary propositions have been considered as requiring great study and ap- 

 plication. 



We may also be able to rendex.an miportant service to society, and to con- 

 fer, a still more essential benefit on individuals, by repressing the premature 

 zeal of unskilful inventors^ , Weuepd g}}\y read over the monthly accounts of pa- 

 tents, intended fo;?. securing the pecuniajiy advantages of useful discoveries, in 

 order to be convinced what expense of time and fortune is continually lavishr 

 ed on the feeblest attempts to innovate and improve. If we can be successful 

 in convincing siich inconsiderate enthusiasts of their r^al ignorance, or if we 

 can show them, that even their own fairy ground has been preoccupied, we 

 may save.thep} from impending ruin, and may relie,v.e the public from the 

 distraction of having its attention perpetually excited by unworthy objects. 

 The ridicule attendant on the name of a projector has been in general but too 

 well deserved ; for few, very few, who have aspired at improvement, have ever 

 had the patience to submit their inventions to sujch experimental tests as cominou 



