Foreign Literature and Science, 177 



An examination of the intervals which separate the years 

 remarkable for great heat, shows that their return is subject 

 to no regular law ; sometimes the intervals are very long, 

 sometimes very short : thus in the last thirty years, they are 

 nine, seven, four, two, one and six years. — Bib. Univ. Dec. 

 1827. 



20. Necrology. — The following are the epochs of the 

 death of the philosophers whose names are mentioned. 



Schubert, - - - 22d October, 1825. 



Fuss, .... 23d December, 1825. 



Reichenback, - - 12th May, 1826. 



Frauenhofer, - - 7th June, 1826. 



Bode, .... 23d November, 1826, 



Laplace, ... 5th March, 1827. 



Volta, the same day with Laplace. 

 Chladni, - - - 4th April, 1827. 



R,amond, - - - 14th May, 1827. 



Fresnel, - - - 14th July, 1827. 



Ferrussac''s Bui. Juillet, 1827. 



21. Sideroscope. — An instrument has been invented in 

 France to which the above name has been given, provision- 

 ally from the extreme facility and delicacy with which it in- 

 dicates the smallest portion of iron in any substance, min- 

 eral, vegetable, or animal. 



It consists, briefly of a small straw, nine inches long, 

 through one end of which pass at right angles, two fine 

 sewing needles, sixteen lines in length, both strongly mag- 

 netised, weighing only one grain. They are inserted in con- 

 trary directions. Through the other end passes a single 

 sewing needle, of the same length, weighing a grain and a 

 half, magnetised in the same manner. This instrument is 

 suspended inside of a glass case, by a single untwisted fibre 

 of raw silk, twelve inches long ; substances to be examined, 

 are introduced into the case, by a lateral opening. The 

 whole instrument weighs but four grains, and the utmost care 

 is observed to exclude from the frame or table of wood 

 which supports it, the smallest particle of iron, and to avoid 

 the disturbing eflfects of a current of air, and even of the 

 breath. — The substances to be presented for trial, are pasted 

 to a small strip of card or pasteboard, to avoid the heat of 

 the hand or fingers. 



Vol. XV.— No. 1.. 23 



