An examination of the intervals which separate the yea 
remarkable for great heat, shows that their return is subje 
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 yeas. Bib. Univ. Dec. 
1827, ; 
20. Neer y.—The following’ are the epochs of the 
death of the philosophers whose names are mentioned. — 
a Schubert, ries - - 
2. = = | 98d December, 1825, 
- Reichenback, tits 12th May, 1826. 
Frauenhofer, a 7th June, 1826 
@." < - - - 25d November, 1826. 
Laplace, pine lt 5th March, 1827. 
Volta, the same day with Laplace. 
Chladni - - 4th April, 1827. 
Ramond, : - : 14th May, 1827. 
Fresnel, ie 14th July 
5 Iuee 
Ferrussac’s Bul. Juillet, 1827. 
91. 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 whielr it te 
dicates the smallest portion of iron in any substance, min- 
eral, vegetable, or animal. 
It consists, briefly of a small straw, nine inches long, 
sev 1 4 of < . 
half, in the same manner. This instrument is 
magnetised ! 
suspended inside of a glass case, by a single untwisted fibre 
of raw silk, twelve inches long; substances to be examined, 
gre 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 w 
which supports it, the smallest particle of iron, and to avoid 
the disturbing effects 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. 
Vor. XV.—No. 1. 23 
