[ '0+ ] 



the compofition no longer gains in the eprouvette ; this will 

 commonly happen when the proportions of the three materials 

 Hand as follows : 



Nitre. Charcoal. Sulphur. 



3 lbs. 8^ to gioz. 2| to 3i oz. 



The manufacturer may poffibly difcover flill greater variations 

 than I have ftated, as they mufl: evidently be determined by the 

 comparative excellence of his materials ; but by adopting this 

 method of afcertaining their quaHties, (however troublcfome it at 

 firft appears) I can venture to affirm he will in the end be a 

 confiderable gainer. There are various opinions refpeding the 

 liquid moft eligible to moiften the ingredients during the procefs 

 of preparing them for the mill: urine, vinegar, fpirit of wine and 

 water, plain water, have feverally been recommended for this 

 purpofe : I have tried them all without being able to eftablifh 

 any data on which to found a decifion ; yet the volatile nature 

 of fpirits, and the heterogeneous matter to be met with in urine 

 and vinegar, feem to point out a preference due to pure water ; 

 but as this is warmly contefted, and my experiments exhibited 

 no conclufive fuperiority, I will not hazard a determination on 

 the fubjciS. It was my intention, in this place, to have given 

 a formula of the leveral proportions in ufe amongll the different 

 powder-makers of Europe and Afia, had I not been deterred by 

 the apprehenfion of fwelling my letter to a volume : I fhall there- 

 fore confine myfelf to China, as that country claims the original 

 invention, with fome appearance of probability. Having procured 

 fome powder manufadlured at Canton, I analyzed two ounces of it, 

 and after repeating the operation fix times, the mean refult gave 

 the following proportions : 



Nitre. 



