346 PHILOSOPHICAL TRANSACTIONS. [aNNO I67Q, 



two paper leaves : this they roll up to the thickness of a man's arm, and so put 

 it to dry in the sun : and when they would use it, they beat it with a hammer, 

 and being well beaten they break it into little bits, which they put and keep in 

 water for about half an hour in a little pot, and so set it over a gentle fire, 

 stirring it continually till it becomes liquid, and taking heed of keeping it from 

 boiling, which would utterly spoil it. 



The Persians are exquisitely skilful in damaskeening with vitriol; but the 

 nature of the steel used by them contributes very much to the good work- 

 manship. This steel they fetch from Golconda, which is the only kind known 

 that can be well damaskeened. When it is put to the fire to temper it, they 

 very carefully give it only a little redness, like that of a cherry-colour; and in- 

 stead of quenching it in water as we do, they only wrap it in a wet piece of 

 linen cloth ; for if they should give it the same degree of heat that we do to 

 ours, it would become as brittle as glass. 



Description of a New Hygroscope. By Mr. John Coniers, jipothecary and 

 Citizen. In a Letter to the Editor, Oct. 23, 1676. N° 129, p. 715. 



Among many trials made by me for the readiest and best discovery of the 

 change or temperature of the air and weather, I have found out that by apply- 

 ing a hand and a circular index, or a quarter-circle, to a pannel made of duly 

 seasoned deal wood, and that divided or slit in two parts, playing loose in a 

 groove, and only fastened to the frame at each end, you have one of the best, 

 if not the very best contrivance, for that purpose. I have made two several con- 

 trivances of it ; the one I invented about five or six years since ; here explained 

 in the first figure, with some observations made at that time; the other some 

 years after the former : both which I thought fit to communicate to you, to 

 dispose of them as you shall think good. 



So far the letter : which, with the invention and contrivance itself, the editor 

 would have given notice of before this, and at the time when in N° 127 of these 

 tracts the like invention, imparted from Dublin, was described, if he had not 

 then been altogether unacquainted therewith. Wherefore, to do right to 

 the ingenuity of this inventor, the description of this his instrument, in its 

 two several contrivances, shall now be faithfully set down here, with the obser- 

 vations made by the former of them. 



The Explanation of the first Contrivance, in Figure A, PI. 11. 



A AAA is the frame of wood, for the two pannels of deal to play loose in, at 

 top and bottom, to which at the two ends they are fastened. — BB, the two 

 pannels of slit deal, three feet deep, and three feet broad a-piece, with a 



