VOL. II.] PHILOSOPHICAL TRANSACTIONS. 187 



That the natives and inhabitants are healthy, and live to the ordinary age, 

 except such as are employed in melting the lead at the mines ; who, if they 

 work in the smoak, are subject to a disease that kills them, and the cattle like- 

 wise that feed thereabouts. From the bottom of the hills there are many 

 springs both to the north, south, and west ; and those waters are very whole- 

 some, and produce rivers after they have run to some distance from thence. 

 The air is moist, cold, foggy, thick, and heavy. The soil near the surface is 

 red and stony ; and the stones are either fire-stones or lime-stones ; but there is 

 no clay, marl or chalk. 



That the trees have their tops burnt, and their leaves and outsides dis- 

 coloured and scorched with the wind, and grow to no size or height. The 

 stones and pebbles that are washed by the brooks and springs are of a reddish 

 colour and ponderous. Snow, frost, and dew remain longer on Mendip than on 

 any of the neighbouring grounds. 



That Mendip is unusually subject to thunder and lightning, storms, noctur- 

 nal lights and fiery meteors. There are no certain signs above ground that 

 afford any probability of a mine to my knowledge. 



The ore lies in veins as a wall ; and is perfect lead, only on the outside covered 

 with reddish earth. 



The ore is beaten small ; then washed clean in a running stream ; then sifted 

 in iion rudders ; the hearth or furnace is 'made of clay or lire-stone, set in the 

 ground, on which is built the fire, and lighted with charcoal, and continued with 

 young oaken branches, blown with bellows by men's treading on them. — After 

 the fire is lighted and the fire place hot, they throw the lead ore upon the wood, 

 which melts down into the furnace ; then with an iron ladle they take it out^ 

 cast it upon sand, and into what form they please. 



Magnetical Variations. By M. Petit, N" 28, p. 527. 



Nothing can be more agreeable to me than to discourse on this subject, 

 especially with the philosophers of England, whence the philosophy of the 

 magnet had its rise, and whence also the principal observations of the change 

 of its declination are come to us; so that it is just that the observations made 

 elsewhere concerning the same should return thither as to its source. 



After I had made the experiments that are in Gilbert* and others, I made 

 that of the needle's declination on three different meridian lines, which I traced, 



* An English physician, who published a learned work. Anno 160O, on the load-stone. He \»as 

 bom at Colchester Ij-iOj became a physician in ordinary to queen Elizabeth, and died in 1663, at 

 63 years of age. 



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