130 Scientific Intelligence. 
very gentle heat, in contact with plumbic carbonate. Plumbie 
sulphid is rapidly formed; and the liquid, when deprived of the | 
excess of lead by H,5 and evaporated on the water-bath, leaves 
residue which, on being extracted with absolute alcohol, givesm 
evaporation a substance possessing all the properties of urea— 
. Soc. Ch., Ul, ix, 6, Jan. 1868. GBB 
6. Test for naphthalin.—V our has published the following re 
tion, which he says furnishes an exceedingly delicate test for the 
presence of naphthalin. When this substance is treated with 
centrated nitric acid, and the mixture dilut i oe 
water, a precipitate is produced, which, after bein 
with water and then with dilute alcohol (1 part 90 pr. et. ales 
and 3 water), is placed in a watch-glass with a few drops of pottt 
sic hydrate and potassic sulphid, and evaporated to dryness ontit 
water-bath. On moistening the residue with alcohol, a mag 
— red-violet color is at once developed.—J. pr. Ch., ¢ii, ry “i 
1867. G, BF. 
unprofitable to the many. The reason of this is obvious. 
istry has been and still is a science in which the dis sing it 
tween principles and facts is great beyond any pa art wi 
makes the matter worse is, that the facts are for the pre 
out logical relations and elude the ordinary grasp of ae 
ciations, . e prope 
: the learner finds before him an enumeration of ae 
ties of oxygen, to the effect that it is a gas, colorless, 71 
odorless, of such a density, such refractive power, such 
h radiating po 
suc i 
sb of combustion, he has a lesson that may be mem 
pline, and no venerable authority pronounces it indis 
education, or rewards its acquisition with a certificate 
