Chemistry and Physics. 51 
The mineral therefore is (essentially) s protvar ortho- 
pyrophosphate of lime with pyrophosphate of magnes 
absence of water naturally suggests that its popoatiits must 
have — in contact with some igneous formation. The p 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHysIcs. 
1. On the Direct Combustion of Nitrogen.—K&mMERER has 
described an interesting lecture e experiment to show the direct 
union of the nitrogen and ox ygen of air. Ina cylinder or globe 
about two liters capacity filled with air, a piece of burning 
magnesium ribbon about thirty to forty centimeters long, is 
laced. When the combustion of the magnesium is ended, a 
intense odor of nitrogen tetroxide is sancti and when the soe 
nesium oxide has deposited, the characteristic color of this gas 
: oO 
color when starch tion | is added.— Ber. Berl. Chem. Ges., x, 
1684, lear 1877. “2. B, 
2. the Relative — of Oxygen for Hydrogen and 
Oardonous oxide.—Bun n his “ Gasometric Methods,” has 
e 
hydrogen and carbonous oxide are mixed with oxygen in quantity 
insufficient to burn them both completely, and exploded; from 
which he draws the ons that the atomic ratio of the com- 
ee products (H,O:CO,) is always oe by simple 
changing from one to the other per saltum as the 
portion of hydrogen varies. Horstmann has experimented anew 
in this direction and has obtained quite different results. © 
finds: 1st. That when electrolytic gas and carbonous oxide are 
carbon 
ing ratio. Thus while the hydrogen, relatively to the carbonous 
oxide, varied from 0°25:1 to 2°33:1, from 20 to 70 per cent of 
the mixture being burned, the ratio.of the combustion- products 
(H,0: CO,) varied from 0°8:1 to 45:1. Nothing like a sudden 
change of ratio was anywhere observed. 2d. That when to a 
mixture of carbonous oxide and hydrogen, increasing quantities 
