OQO PHILOSOPHICAL TRANSACTIONS. [aNNO 1749 



mercui\ fell to 28-1- of its equal parts, and by the heat of his body it rose to 66 

 of those parts. This thermometer held into the sproudle fountain rose by its 

 head to 96, and in the mill-fountain to 67. 



About 20 miles from Carlsbad to the south-west near the town of Egra, is a 

 cold spring of mineral waters, much in use in these countries. This gives also a 

 salt much of the same kind. T6 the south from Carlsbad about 25 English 

 miles are likewise several cold springs: one of which is much richer in this same 

 kind of salt than the former. It belongs to the monastery of Toeple. In the 

 winter, when they boil this water, from 10 lb. of water they get sometimes above 

 1 oz. of salt. They prepare here a neutral salt by adding a mineral acid, or per- 

 haps some other neutral salt, (but the preparation they keep a secret) which 

 makes it shoot into beautiful crystals. It is called sal medium toeplicense, 

 and is sold in many places of Germany. On exposing these salts some time 

 to the air, they fall into a magnesia, but dissolving and crystallizing them again 

 recovers them ; though the oftener they are dissolved, the crystals shoot the 

 smaller. 



About 7 miles south-west from Carlsbad, at Altsettle, are mines of black 

 schistus, and formerly they made a great deal of alum and vitriol from it ; but it 

 is now neglected, as they find in the same mines plenty of gleba pyriticosa, from 

 which thev distil sulphur. Six hundred weight of this pyrites give one of sul- 

 phur: and the oven (furnace) makes from 1 to 2 cwt. per week. The residuum 

 being thrown in great heaps in the open air, takes fire, and constantly smokes. 

 This matter they throw into large reservoirs of water, which afterwards they let 

 run off into the boiling-house, and so make copperas. 



About 9 English miles to the south from Carlsbad, are the tin mines of 

 Schlachtenwald. They reckon this mine has been wrought near 500 years. 

 There are 5 entries, 4 of which are provided with machines for hoisting the bar- 

 rels with the tin stone : the 5th is for drawing the water out of the mine. The 

 number of miners who work below ground, are 90 : each man delivers 25 bar- 

 rels of this stone per week, and receives something less than half a crown wages. 

 They have different inventions in the mine for splitting the rock, but the most 

 effectual one is bursting it with gunpowder. The whole people employed in 

 these mines are about 300. The main body of the mine is nearly 700 feet in 

 diameter, and from this go several east and west; for so the mineral runs. The 

 broadest of these ways is about 2 feet, and the mineral in these veins is richer 

 than what is found in the main body of the work, whose greatest depth is 650 

 feet. The tin-stone is first burnt in kilns, which they say betters the tin consi- 

 derably, and makes it much more easy to stamp. After this preparation it is 

 brought to the stamp mills, where by stamping it becomes like grey river sand, 

 which they wash, and separate the tin from it in the following manner. They 



