f 



consi 



+ * 



394 Foreign Literature and Science. 



lisbman, on learning the situation of this marsh, undertook 

 to drain it ; and in the course of a year from its commence- 

 ment, the work was completed, and this vast tract which 

 was only a reservoir of unwholesome miasmata was con- 

 verted into a feitile soil, adapted to the various agricultural 

 productions. This prince having tried all the pleasures 

 which fortune and high rank can yield in the luxuries of a 

 court, has retired to his estates, and finds in a devotion to 

 objects of utility and to the amelioration of his people, the 

 secret of being truly happy. IdeniB 



38. Galvano-mas'nciic-condenser, — A delicate instrument 

 for exhibiting the magnitiferous property of a weak gal- 

 vanic combination, has been invented by M. Poggendorf of 

 Berlin. It is simply a wire rolled in the form of a spiral 

 so as to make thirty or forty turns. The wire is covered 

 with silk in the same manner as the large cords of a harpsi- 

 chord are with fine wire. The spiral is placed vertically, 

 and a steel needle, not magnetic, is suspended horizontally 

 within it, on a vertical pivot. Thus arranged, if one end 

 of the spiral be brought into contact with a zinc plate, and 

 the other end with a copper plate, and the zinc and copper 

 be each connected with a humid substance, or water acidu- 

 lated with nitric acid, — the needle soon acquires polarity, 

 and arranges itself in the magnetic meridiaii, M. Oersted 

 considers a needle thus mounted as a gahanoscopr. much 

 more sensible than a prepared frog. Ed. FhiL Juur. 



39. Jl sofi crystal of quartz. — In a memoir on the mar- 

 ble of Carara in Italy, by Em. Repetti, the foilowiag sin- 

 gular fact is mentioned by the author. 



In the spring of 1819 'Mr. del Nero proprietor of one of 

 the quarries in the Vossa del I'Angelo, in suwing out a large 

 block destined for a column in the temple of St. Francois 

 at Naples, discovered in the interior of the n^arble, what the 

 workmen term a Zwaca, viz. a crystal of calcareous spar of 

 considerable size. In digging this out they found a cavity 



in the marble lined with crystals of quartz, and containing 



«U^.**_ ^. 1 __t_ f 1/* ^ \* •■! /- -t - ^--i+fiori 



about 



si 



30ut a pound and a half of liquid perfect!} transparent and 

 igluly sapid. They observed with surprise in this cavity 

 a protuberance as large as a finger, transparent and which 

 appeared to have all the characters of a rock crystal of that 



