250 On the d'lff'acjit Kinds of CaJni'ui, and 



3cl, Afky-rocket, of a large diameter, would be of equal 

 fervicc. It would alfo carry, from !he vefll-l to the ftiore, a 

 Itring capable of drawing a rope after it. C. Ruggieri, whom 

 I have confulted on this fubjed, told me, that he made fome 

 four inches in diameter, which rofe to a great height ; and 

 that, wich a ftring attached to them, they would go to the 

 diftance of four or five hundred fathoms, which is more than 

 would be neceffary. They may be kept in a ftate fit for 

 fervice two'years, if depofited in a dry place. 



Ladly, A fourth plan for faving the crew of a fhipwrecked 

 veflel, is that of throwing from the vefiTcl into the fea an 

 empty cafk with a cord attached to it. The wind and the 

 waves would drive the calk to the (liorc, and afford the means 

 of eftablifliing that rope of communication already men- 

 tioned. Each of thcfe methods may be improved, but I 

 cannot at preient enter into any detail *.. 



V. On the different Kinds of Cadmia, and particularly thofe 

 0/ Zinc and Cobalt. By I. I. Binuheim of Mofcozv f . 



X. HE fureft method of claffing minerals is vi ithout doubt 

 to arrange them, not according to their external charafters, 

 but according to their internal component parts. For, though 

 the former in fome meafure ferve for difcrimination, and 

 are therefore not altogether ufclefs, they are not fo preclfe 

 and certain as to form a bafis for a fyltem of mineralogy, 



• The author of the above jnpLTs lays, tli:it h.j announced his difcovery 

 in the AJricbc-: clc Paris on the 19th of January i 794. However this ni iy 

 be, vve know thit one of his mtthods, that of conveying a rope to the 

 fliorc, by attacliing it to a builct or bomb to be aftcrwauls fired from a 

 cannon or mortar, was propofed a few years ago by a lerjcant or officer of 

 artillery at Woolwich, named Bell. Some experiments of the fame kind 

 made at I'orifmouth, we believe, anlwired expectation. The ufe ef a kite or 

 rocket feems to dcltrve attention ; and v.c do not hefitate to fay, that the 

 former could hardly fail of producing the defircd effeft. At any rate it 

 mijjht be eafily tried. Ediior. 



■\ from Nc'ue Nordifeke BjirS^e, by rrofeffyr Tallas, Vol. VI. 



