PREFACE. vii 



In the following treatife I have attempt- 

 ed to bring together the befl and moffc 

 material things which have been delivered 

 by different authors. And, having myfelf 

 many times gone through the praclice of 

 the four different parts into which I have 

 divided the fubje6l, I have thence taken 

 occafion to mention fuch improvements as 

 I had a6lually tryed, and alfo to fuggefl 

 fuch as I had reafon to think would, on 

 tryal, be found ufeful : by thefe means 

 attempting to impart what I already knew^ 

 and dire6ling to fuch tryals as might dif- 

 cover more than I knew, and flriving to 

 enter fo far into the reafon of things, as 

 jiTiight give fome light to future difcoveries. 



If fome fhould think I have treated the 

 fubje6l too minutely ; I can only fay, that 

 this was owing to my obferving that bre- 

 vity in rules which were to be put in prac- 

 tice was often the caufe of obfcurity and 

 error. 



If inaccuracy of exprefTion fhould oc- 

 cur, I can only offer in excufe the multi- 

 tude and variety of precepts, where the; 

 mind, while exercifed on the matter, muft 

 be often inattentive to the form. 



A 4 li 



