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1 believe moil of them have been printed, but if 

 there are any which have not, or that can amufe 

 you or inftruct others, you are welcome to ufe them 

 as you pleafe : I only wifh they may contain any 

 thing ufeful. While he lived, I purfued thofe flu- 

 dies j but, foon after his death, new fcenes arofe, 

 and engaged me more in practical fervice, than al- 

 lowed me time for theory, or experiments. I am., 

 however, a conflant weli-wiiher to the progrefs of 

 arts and fciences, as well as ftudy j and very much, 



SIR, 



Your obedient, 



humbleiervant, 



Jn° Calk 



SfflA 



