Chemistry and Physics. 58 
ampere ammonia, or ammonium sulphydrate.—C. Z., war 1036, 
ay, 1876. B. 
OMe Metalic Cer ee Lanthanum, and Didymium. oe, roe E- 
BRAND and Norron, in Bunsen’s laboratory, have obtained, by 
the electrolysis of the cerium, lanthanum and didymium chlorides, 
the metals in quantities sufficient for careful investigation. As 
proof of the puri ity. of the mag inane emp! (Doge. ee refer to the 
Its kindling thinparatiixe is air oxygen is much lower than 
magnesium. Pieces scratched off inflame, and the wire 
ignited in a flame burns more brilliantly than magnesium wire. 
It Seria ‘hes heated in chlorine, less readily in bromine vapor, 
and without incandescence in iodine vapor. Water at common 
peratures is ae decomposed by it; cold concentrated sul- 
phuric acid and cold red fuming nitric acid do not attack it, but 
these acids pr “aitibe, and also hydrochloric acid, dissolve it. 
Metallic hty reer is much like cerium in its gen neral chemical 
deportm t, but by concentrated nitric acid it is easil attacked. 
nent in air, and even in dry air its color soon diiiges to a steel 
blue, — The by Siac gravity of a piece deposited by meg 29 
Its miclting point appears hea ear that of cerium, hey pra 
indling te emperature is hi shoe Small pieces from filing or strik- 
ing on flint do not be Sots ante rag in the air, but burn bril- 
liantly in the flam Their analysis shows less than one per cent 
Impurity in oe 8 imen ‘. 
Metallic’ didymium is more like lanthanum than cerium; it 
not less pce ductile or permanent in air than lanthanum, nad 
has about the same hardness ; its color is not as white, and moist 
air turns it ‘yellow. Fine particles of the metal do not ignite 
Te a oon in the air, but burn when heated in a lamp 
fusion has a a specific gravity of 6-544. —Pogg. Ann. a a wee 
8. On Gentisin—Huastwetz and Hanermann have pebtiohed 
& Second paper on Gentisin, a crystallized non-nitrogenous body 
from gentian root (Gentiana lutea). In their a 
Paper they showed that under the a apeen om a ie. 
nese lits up into phloroglucin C,H,O, 
rmula & H,0,, to sales the gave the name "geste acid, 
