and Iron- Stones Ij Fufion. 1 8 1 



five mluutes will deftroy i-icth of the produce of metal, 

 while the incumbent fluid protefts the furfacc of the metalhc 

 button from the aftion of the atmofphere. 



It is not, however, mv province to enter mto a mmute 

 examination of the produfts obtained from tbeufeofluch 

 vitreous fluxes, which are always produftive of the moft oxy- 

 crenated ftate of crude iron ; and the accuracy of whofe re- 

 fults under a ftate of fuch high oxygenation, are always to 

 be fufpeaed. I have frequently proved that, in ufing them, 

 the afilnitv of the metal was fo great to oxygen, that a flight 

 deran<rement of the crucible, which had thrown the vitrid 

 fluid from anv point of the furface, was immediately attended 

 by a rapid deflagration, and a confiderable portion of the 



iron oxvdated. _ r > r 



I fliall chiefly confine myfelf to a communication of thofe 

 fafts which I have repeatedly confirmed, with a view of ex- 

 tend-.n<r my refults and obfervations to a more cxtenfive fcale. 

 I have°conftantlv cnnfidered the aflay-fumace as capable of 

 afl-ording conclvfion. applicable to the operations of the 

 fmeltin^-furnace, and that change or innovation flioulc. al- 

 ways have the concurring teftimony of truth to back them, 

 thoucrh, on a fmall fcale, before they be rifqued on one more 

 mom° ntous or extenflve. Influenced by fuch motives, T 

 rarlv rejeaed, as tota'.ly inapplicable to the fcale of manu- 

 fafture, the numerous tribe of falts, alkalies, and earths: 

 thefe, in the application, are fabjca to no rule, nor guided 

 by any immediate objea of general utility, but are as arbi- 

 trary as their authors are numerous. On the contrary, I 

 have direaed my endeavours to the ufe of fuch agents as 

 eflea L-paration upon the large fcale, and have been fo.t i- 

 nate to find that the fame folvcnts, when properly applied, 

 are produaive of the moft perfed and finiflicd refults. By 

 the Ample application of lime or chalk, in various propor- 

 ti-ms, as a calcareous earth, and co nni<.n bottle glaf<, .n the 

 p'acc of filex, to conftitutcfulibility, I have hccn able to pro- 

 duce in ih^ afl-ay-fumace all the various qualities of crude 

 N 3 iron> 



