Chemical Science. 441 
of time, &c., that I was able to satisfy myself there was no 
anomaly in the phenomena. 
13. Metallic Titanium.—Dr. Wollaston has lately discovered 
that the small cubic crystals of a metallic lustre and reddish 
colour, which are occasionally found in the cavities of the slags 
from iron furnaces, are pure titanium. 7 
14. Congelation of Mercury.—M. Gay-Lussac states, in a 
memoir on the cold produced by the evaporation of fluids, that 
he has readily frozen mercury, by surrounding it with a frigorific 
mixture of ice and salt, in the apparatus in which aqueous vapour 
is produced and absorbed by the process of Mr. Leslie; and 
hehas no doubt that, with analogous means and very vapourable 
liquids, a degree of cold might be produced below that pro- 
duced by mixtures.—Annales de Chimie, xxi. 85. 
15. Variation of Thermometers.—M. Flaugergues, in a letter 
to M. Pictet, points out an effect in certain thermometers, con- 
sisting of a gradual elevation of the freezing-point of ice. It 
takes place with those mercurial thermometers which, being 
hermetically sealed, have a perfect vacuum above the mercury. 
In some cases this elevation has risen to .9 of a degree, and has 
gone on increasing for years together. In examining into the 
cause of this effect, M. Flaugergues soon observed that it did 
not take place with mercurial thermometers open at the top, or 
with alcohol thermometers ; and he was led to attribute it to 
the constant pressure of the atmosphere on the bulb of the 
instrument.. He thinks that the glass gives way by degrees 
. to this pressure, just as any elastic spring will do under a con- 
stant force, and this gradually produces the effect observed. M. 
Flaugergues thinks, therefore, it would be better to make mercurial 
thermometers with open terminations, introducing a small plug 
of cotton to keep the dirt from entering, or in some cases 
even closing the aperture by some elastic substances, as caout- 
chouc, &c.--Bibliotheque Unwerselle, xx. 117. 
16. New Electro-Magnetical Experiments. Ampere.—'Two 
very interesting electro-magnetic experiments have lately been 
made by M. Ampere, in the laboratory of M. de la Rive at 
Geneva. M. Ampere had been induced, from his mathematical 
investigations, to expect a repulsion between two portions of an 
electrical current passing in the same direction, and in the same 
right line, or that every part of an electrical current would repel 
the other parts, a result which may be comprehended by conceiving 
an endeavour in the current to elongate itself. The experi- 
ment which M. Ampere has contrived to illustrate this action of 
the current, and which our readers may compare with one 
