Arts. 405 



which coating I dare not deftroy to examine the materials 

 of the ball ; but from its weight it mult be metallic, yet it 

 floats high in the fluid. Since he took it from this place, I 

 perceive he has marked it with lines of longitude and lati- 

 tude, like a geographical fphere. This, I prefume, he has 

 done on his voyage outward, the journal of which is likely 

 left in America. But this which I poffefs begins with the 

 exacT point of latitude and longitude of Philadelphia, and 

 records the zenith of every day as accurately as if he had 

 been all along on terra flrma. In bed he told the captain 

 his diftance from the coaft of Ireland to a minute, by look- 

 ing at his machine. 



" The properties of magnetifm are not yet fufficiently 

 known, and they have heretofore been applied to ufe only 

 in the form of the needle. But it appears to poflefs, betides 

 its well known polarity,' a propensity to retain its native re- 

 lative pofiti on on the earth; that is to fay, it turns upon an 

 axis, like the earth, one point always pointing at the pole 

 ilar. Beyond the line, this point upon the ball is below the 

 horizon ; and on the (hores of America the longitudinal 

 line, which now is its meridian, was far down the fide : fo 

 that, if he had failed round the earth, his little ball would 

 have made a complete revolution upon its axis." 



ARTS. 



We mentioned fome time ago that a French artift had dif- 

 covered a method of foldering glafs when broken. This art 

 we now underftand has been carried fo far towards perfection, 

 that two plates of the fize of eighteen inches may be joined 

 together. 



Another artift of the fame country has found out the 

 means of rolling plates of glafs in fuch a manner as to ex- 

 tend them fome inches each time they are paffed through 

 the rollers, as would be the cafe with metal. The procefs 

 has not yet been made public ; but we apprehend that a part 

 of it muft confift in fubjecting the plates, after the firft cart- 

 ing, to fuch a heat as may make them fufficiently plaftic to 

 go through the operation once, and fo again for a fecond and 

 iubfequent rollings, till the required extenfion be given to 

 them. 



The alloys of gold with platina have hitherto been fup,- 

 pofed to depreciate the colour and malleability of the precious 

 metal in fuch a manner as to prohibit their ufe. It appears, 

 however, from fome late experiments made by an ingenious 

 jeweller, Mr. Francillon, that a mixture, confiding of fix 

 parts of gold and one of malleable platina, gives a metal of 



C c 3 a beautiful 



