258 Scientific Intelligence. 
**] cannot conclude this letter without expressing a hope that since 
gases are shown to be magnetically affected, they will also shortly be 
found, when under magnetic influence, to have the power of affecting 
light, (Experimental Researches, 2/86, 2212.) Neither can I refrain 
from signalizing the very remarkable and direct relation between the 
forces of heat and magnetism, which is presented in the experiments 
on flame, and hehted air and gases. I did not find on a former occa- 
sion (Experimental Researches, 2397) ny solid diamagnetic bodies 
were sensibly affected by heat, but shall repeat the experiments and 
make more extensive ones, if the Italian philosophers have not already 
done so. In reference to the effect upon the diamagnetic gases, it may 
be observed that, speaking generally, it is in the same direction as that 
of heat upon iron, nickel and cobalt; 7. e., heat tends in the two sets of 
cases, either to the diminution of magnetic force, or the increase of dia- 
magnetic force ; but the results are too few to allow of any general con- 
clusion as 
‘ As air at different temperatures has different diamagnetic relations, 
and as the atmosphere is at different temperatures in the upper and low- 
er strata, such conditions may have some general influence and effect 
upon its final motion ~ action, subject as it is continually to the mag- 
netic ——s of the earth.” 
2. the ida on of meses Minerals on their specific grav- 
ity, (Berz. Joncas 1846, 15.)—The fusion of a crystallized 
mineral produces, as has been pine a glass of different specific grav- 
ity. According to the — of Deville, (Jour. f. Pract. Chem., XXXVI, 
295,) there is a change i 
Sp. gr. of crystals. Sp. gr. after fusion. 
nes from 26894 1 to 25955 or about todo 
fy = 
eldspar, 2561 « 2°351 
em * vo BRI69: S. .. 28256 " 2 
Pyro “ 32667 “ 28055 s : B 
Peridot | pam Fayo,“ 33813 “ 2-8517 “ % 
rysolite is commonly evn and this Fayo specimen ivi have 
consisted largely of silicate of i 
Brongniart has shown the eorrteponiditiy fact that porcelain biscuit 
has a specific gravity of 2°62; but after ba aking, it is only 2 242 
According to Rose, s (Fong. oie ‘Ixvi, 97, ) the Berlin porcelain changes 
in the same ma anne Feldspar diminishes according to his experi- 
porcelain, afier baking, is reduced to a specific gravity 2°452, which 
exceeds the diminution i in the ingredients alone, and indicates according 
to Rose, the union of the alumina into a new chemical psa 
which in a semi-vitreous condition has this small specific gravity. 
3. anor and sey He acetic acids. —The eee these acids 
i M. simntina (Che em. Gaz., Nov. 1, 1847, p. 433, from Jour. 
an m. Méd., viii, p. 425, August, 1847.)—To determine the amount 
sypsum occurring naturally or as an adulteration in common salt, 
