354 Miscellanies. 
tions of nitric acid are by degrees to be added,—then evaporate to 
dryness, and heat the resulting chloride to the melting point. It is 
thus transformed into a brown crystalline chloruret.. Ten parts of 
this are to be mixed with six parts of anhydrous carbonate of soda, 
and’ heated in a covered crucible to dull redness. Treat the mass 
with water in order to dissolve the marine salt that will be formed,— 
the protoxide of copper separates in a beautiful red powder, not 
ce oe which is to be washed and dried. 
If sal ammoniac is added to the above mixture, the whole of the 
chloruret is reduced, as might easily be foreseen, and the metallic 
copper separates in a isieenete divided, spongiform mass, on the ad- 
dition of water.—Ann. de Chimie, Juillet, 1831. 
8. Estimation of the bleaching power of chlorjde of lime—M. 
Marozeau proposes to employ the protochloride of mercury for this 
purpose. Being insoluble in water, and even in hydrochloric acid, 
it becomes by the addition of chlorine changed to the deutochloride, 
and is then immediately soluble. 
_ His method is this,—take a solution of protonitrate of mercury, 
add a more than sufficient quantity of hydrochloric acid to precipi- 
tate all the mercury in the state of protochloride, pour into the liquid 
a solution of the chloride of lime—the chlorine, set free, acts on the 
precipitate, which gradually diminishes, and the process is to be stop- 
ped at the moment when a drop of the chloride of lime completes 
the entire solution. The quantity of the chloride of lime, used for 
a fixed quantity of the test liquid, indicates the strength of the chlo- 
rides. The author has formed:a table which agrees with that of Gay 
Lussac.—Idem, Avril, 1831. 
g. iene of gunpowder under water.—In dhe port of Pene- 
mund, (says Prof. Hiinefeld of Greifswalde,) there was situated an 
enormous rock, covered with water about three feet, which was a Se- 
rious impediment to the navigation. Efforts had been made, but in 
vain, to remove it, by mechanical force, and it was not known by 
what means it could be blasted. The difficulty was at length over- 
come by Engineer Liibke. 
A leaden iube, several feet long and closed at the lower eos was 
inserted i into a hole, bored several years before, in the rock. A car- 
Was pushed to the bottom, and in contact with the powder over 
it, a little pince. of potassium. The upper part of the tube was fun- 
