JJ4 Experiments and Objervahons 



21. To difcovcr in what ftate (with refpcel: to electricity) the* 

 vapour was, 1 ufcd the apparatus reprefented by the annexed 

 (ketch, of which the upright A B is of glafs covered with 

 failing- wax, and all the veil, except the bottle of the electro- 

 meter, is of metal. In thirteen trials with cinders of pit-coal, 

 the electrometer diverged I\ fevfcft limes; four times it 

 opened and clofed again before 1 could determine which 

 Hate was produced, and twice it did not diverge at all. 



22. In feven trials with marble, the electrometer diverged 

 N. three times ; three times it loft all its divergence before 

 I could determine in which Hate it diverged, and once it 

 did not diverge at all. 



In the two laft experiments, the electrometer retained its 

 divergence fo fhort a time, that 1 was obliged to hold ail 

 excited tube in one hand, while I dropped the hot fuhftance 

 into the water with the other, to be ready in time to -de*, 

 terminc the (late produced by the vapour. ! 



• ' : — ■ — : 



XXXIX. Experiments and Objervaiwns on the Manufaelurs 

 of Malleable Iron direct ty from the Ore. jB^D.MdsheTj 

 Ffq. of the Colder Iron IVorh *. 



i 



N a former communication T took occafion to remark 

 that a variety of proceiies had been followed out, endeavour- 

 ing to form a good quality of bar iron with coak-pigs and 

 pit-coal; but as thefe had been attended with little or no 

 alteration of principle, the remits had been nearly fimilar. 

 In no cafe has an uniform quality of bar iron been produced, 

 able to cope for all ufes with the fupcrior marks of Sweden 

 and Ruffia. 



At this day, affifted by a variety of facts chemical and phi- 

 lofophical, we yet remain in comparative ignorance of what 

 constitutes the real difference in point of quality betwixt home- 

 made iron and that imported from foreign markets. We 

 acknowledge with pain and humiliation our dependence on 

 other countries for our fteel-iron, and it is with regret that 

 we fee every induftrious exertion made to obviate this depen- 

 dence foiled by the nature of our fuel, or the defective qua- 

 lities of our ores. 



I Thofe who have voluntarily made an offer of their time 

 and abilities for the fervice of their country, in promoting 

 a thorough knowledge of the principles of our manufactures, 

 could not engage in a fubject fraught with more important 



* Communicated by the Author. 



con- 



