388 ‘Natural-Philosophical Collections. 
New Principle in Albumen.—M. Couerbe has discovered a new principle in 
albumen by exposing to a cold of 32° Fahr., and a few degrees below it, con- 
centrated solution of white of egg. At the end of a month the mass became 
thicker, and yielded a membraneous net work, which is solid, white, translucent, 
insipid, and inodorous, and easily reduced to powder. Muriatic acid is the 
best solvent of it, and when water is added, it becomes of an opaque white, and 
deposits a powder of a very high degree of tenacity.—See Ann. de Chim. a xl. 
P- 323- 329. 
On the Natural Metallic Compounds which cover the Surface of Antiques ; 
by M. BEcQUEREL.—Mr. John Davy found in the sea an ancient Greek hel- 
met, whose surface presented remarkable decompositions : it was covered with a 
crust of carbonate of lime, below which were found a multitude of little octahe- 
dral crystals of pure shining copper; the remainder of the decomposed part was 
formed of a sub-carbonate and a sub-chloruret of copper. 
These decompositions are easily explained after the recent observations of M. 
Becquerel on the mode of action of electrical forces of low intensity. (See No. 
IV. of this Journal, p. 309.) The calcareous deposition being once formed in 
certain portions of the surface of the helmet, the liquid enclosed below it, and 
with difficulty communicating with the external fluid, was able to saturate itself 
with copper by slow degrees ; on the other hand, the ‘exposed go Oes of the hel- 
met being submitted to the constant action of the sea water, the negative electri- 
city disengaged during the action was driven into the interior of the metal ; im- 
mediately the part Seaaed under the crust became the negative pole of a little 
pile which commenced to act on the dissolution of the copper in contact with it. 
According to the electricity of the pile, we have metallic copper in octahedral 
crystals, or crystals of the protoxide of the same metal, as in the apparatus con- 
trived by M. Becquerel to form similar bodies. Mr. John Davy has also disco- 
vered an antique leaden sling, covered with crystals of carbonate of lead, whose 
formation is still more easily explained, according to the ideas of the author. 
M. Becquerel has done more, he has produced on a plate of lead, after some 
days, hy means of alk tiee Gheancal processes, a decomposition smalosous to that. 
which the old sling presented. He has caused it to become covered with crystals 
oi carbonate of lead. 
M. Becquerel has been curious to visit the medals and other antique objects 
deposited in the Royal Library ; but he has not been able to make the observa- 
ions he desired, on account of the coating having been removed from them. He 
remarked, as it has been previously observed by antiquaries, that there is an evi- 
dent relation between the nature of the formation in which these metals are dis- 
covered, and that of the decomposition whiich they undergo. He indicates the 
nature of the substances which colour them in every instance, and explains the 
whole admirably according to his theory. 
It is desirable, says M. Becquerel, that the interior of mines should be visited, , 
for the purpose of examining the metallic compounds which they contain. There 
is reason to believe that our present knowledge of the mode of formation of these 
bodies, would lead to curious ideas on the nature of the forces which are now in 
activity on the surface of the globe. 
Observations on the Ioduret and the Chloruret of Nitrogen, &c. ; by M. 
SERULLAS.—The results which M. Serullas has obtained, are as follows : ) 
1. The ioduret of nitrogen decomposes water, producing the iodate of am- 
pees 
. Ammonia is formed in most cases by the decomposition of the ioduret of 
sea ent ; which at first induced the supposition that this alkali entered into the 
‘eomposition of the fulminating ioduret. ied 
3. The chloruret of nitrogen, submitted to the action of different substances, 
as sulphuretted hydrogen, phosphorus mixed with carburet of sulphur, sulphur, 
