574 PHILOSOPHICAL TRANSACTIONS. [anNO iS/l. 



to the blowing-house in little canvas bags on horses) that is to be burned, is 

 laid on the top stone, the kiln being thoroughly heated before, and at the hole 

 above-mentioned cast down on the second or bottom stone; at the mouth of 

 which stands a man with an iron coal-rake, to give notice when enough is let 

 down to cover the stone all over about three or four inches thick, which he 

 performs with his rake: The hole at the top is immediately covered with green 

 turfs, that the flame may reverberate the stronger. The rakeman, after this, 

 constantly moves the tin with his rake, that all parts of the mundic may get 

 uppermost ot the tin, and so be burned away; which we know by the flame, as it 

 will then become yellow, and the stench lessen; for while the mundic burns the 

 flame is blue. Then with his rake he thrusts it down, at the open place be- 

 hind, into the open fire, and then receives a new supply of tin from above, as 

 before. Now when the place beneath, where the fire is made, grows full of 

 tin, coals, and ashes, with his rake he draws it forth with the coals on the little 

 square hole on the one side near the back, where the ore, fiery hot and red, 

 lies in the open air to cool; which will scarce be in three days, because of the 

 coals that lie hid in it : But in case we cannot stay so long, then we quench it 

 with water, and is like mortar. Although we let it cool of itself, or with 

 water, we must new tramble it or wash it, before we put it into the alman fur- 

 nace. And because I have set down the proportions of ore and fire already, in 

 the answers to the mineral queries, I will not repeat them here, but only add 

 an observation or two, and then dismiss this subject. Moor-tin (i. e. such as 

 is dug up in the moors) runs or melts best with moor-coal, charked : But our 

 tin which lies in the country, runs best with an equal proportion of all charcoal 

 peat (/. e. moor-coals) for the first running; but when w^e come to remelt our 

 slags, then we use charcoal. When all is melted down and remelted, there 

 sometimes remains a different slag in the bottom of the float, which we term 

 mount-egg ; and that it is mostly an iron body, though of a tin colour, I acci- 

 dentally assured myself by applying one of the poles of a loadstone to it, which 

 quickly attracted it, yet not so strongly by far as that of iron. 



Jn Account of two Books. N" 69, p. 2114. 



I. Prodromo overo Saggio di alcune Inventioni nuove premesso all Arte 

 Maestra di P. Francisco Lana della Campagnia di Jesu, in Brescia, 1670, 

 in 4to. 



This introduction is premised to a work, designed by the author to show the 

 value of the principles and knowledge of natural philosophy, by some of the 

 more considerable inventions and experiments hitherto found in authors, and 

 other new ones of this writer himself. 



