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the////, or iron pan, over the fire. For this ex^ 

 pcriment, (hallow vefTels will be fufficicnt. It mud; 

 not be heated to boil j for that would be likely to 

 drive off by fleam* what we want to retain. Let 

 the evaporating vefTel be. <X)vered, dviring the pro-^ 

 cefs, with a wooden lid, through which a nunnber 

 of holes are bored with a gimlet, as the fleam will 

 fly off much quicker this way, than if left unco- 

 vered ; and for this reafon, that in the latter cafe, 

 the air, prefling on the whole furface, would pre- 

 vent the fleam froiji rifiug fo freely as it will do 

 through a number of fmall apertures.f 



You will be pleafed to obferve. Gentlemen, that 

 iny firll objed was, to get this extradl made in 

 America, from whence krge quantities of rough 

 bark were annually imported: but the unhappy 

 flate of the colonies prevents its taking place there 

 at prefent. In fome future time, perhaps, the at- 

 teix\pt CD.ight 13eceed ; and as the fun is much 

 Ixfttter there in fummer than with us, the evapora- 

 tion might be made by its heat, without the ex- 

 pence of fire. 



^In thi^ ^int, w-e thi>nk oar corrcfpondent mifUken; being-qf 

 the opinion, that boilhig would not calife any evaporation of tliQ. 



t In this refpc^l alfo we think the Author miftaken. , 



In 



