INTRODUCTION. 3 



inventions of all kinds, we may proceed in the most direct manner to con- 

 tribute to the dissemination of that kind of knowledge which is most parti- 

 cularly our object. So that we must be more practical than academies of, 

 sciences, and more theoretical than societies for the improvement of arts ; | 

 while we endeavour at the same time to give stability to our proceedings by 

 an annual recurrence to the elementary knowledge which is subservient to 

 the purposes of both ; and, as far as we are able, to apply to practice the 

 newest lights which may from time to time be thrown on particular 

 branches of mechanical science. It is thus that we may most effectually 

 perform what the idolized sophists of antiquity but 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 

 subservient 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 sup- 

 ported by the head that directs ; and much labour is lost for want of a 

 little previous application to the fundamental doctrines of the mechanical 

 sciences. Nor is any exorbitant portion of time or industry necessary for 

 this purpose ; for it happens singularly enough, that almost all practical 

 applications of science depend on principles easilyjilearnt ; and, except in 

 astronomy only, it has seldom been found that very abstruse investigations 

 have been of great importance to society. Our most refined analytical 

 calculations are by far too imperfect to apply to all possible cases of me- 

 chanical actions that can be proposed ; and those problems which most 

 frequently occur, may in general be solved by methods 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 

 application. 



We may also be able to render an important service to society, and to 

 confer a still more essential benefit on individuals, by repressing the pre- 

 mature zeal of unskilful inventors. We need only read over the monthly 

 accounts of patents, intended for securing the pecuniary advantages of 

 useful discoveries, in order to be convinced what expense of time and for- 

 tune is continually lavished on the feeblest attempts to innovate and 

 improve. If we can be succcessful in convincing such inconsiderate 

 ; enthusiasts of their real ignorance, or if we can shew them, that even their 

 own fairy ground has been pre-occupied, we may save them from impending ; 

 ruin, and may relieve the public from the distraction of having its atten- 

 tion 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 such experimental tests as common sense 

 would suggest to an impartial observer. We may venture to affirm that 

 out of every hundred of fancied improvements in arts or in machines, 



B 2 



