256 Scientific Intelligence. 
apinhs and then precipitated by a standard solution of sulphuret of so- 
diu The mode of agente: is precisely the same as with copper, 
st this letieval, ii Ser., vol. ii, p. 259,) with this difference, that as the 
equivalent of lead is higher Rd that of copper, the solution of sul- 
phuret of sodium should be diluted with. three parts of water. This 
method gives results within one per cent. ; and sometimes much nearer. 
Tin, antimony and arsenic, do not interfere with the suerne and it 
is not necessary to filter from the insoluble oxyds. Iron, = , and 
cobalt, although not often met with in the assay, are said not affect 
the result. Zine precipitates after the lead, and by the hist in BB 
of the ceils in fact assists in determining the total absence of 
When copper is present it is first determined by the method of Pe- 
louze ; a like per-centage of copper is then added to one gramme of 
pure lead and the analysis of the — shows how many divisions 
are to be subtracted on account of the copper 
Bismuth interferes with the estimation of the lead, but from its high 
G. G, Be 
e Solubility of Alumina in Ammoniated Water; by F. 
iets and J. Durocuer, (Ann. de Chim, ovaat Phys., Aug., 1846, and 
mp- Rend., May, 1846.)—This research is intended to establish j— 
That if ammonia is employed to precipitate alumina in the absence 
of ence salts, a very considerable proportion may remain in the 
solution 
That sk quantity of ammoniacal salt, necessary for the commie 
precipitation of the alumina, increases with the volume of the solution; 
That even in the absence of salts of ammonia, the alumina may be 
entirely precipitated from the solutions, irrespective of their volume or 
of the quantity of ammonia contained in them, provided a sufficient 
time be allowed to elapse between the precipitation and filtration, the air 
ar = 4 carefully excluded ; 
the most suitable reagent for the complete ej RES of alu- 
mina, without reference to the volume of the soluti the absence of 
‘salts, or the length of time, is the sulph at of ammonium. 
_ The authors seem to undervalue the precautions given by Rose, Fre- 
senius, and others, for undoubtedly accurate results have been obtained 
by these methods: neither do they assign any determined rate of sol- 
ubility to alumina, which of course is impossible, as spontaneous separa 
tion takes place. Still, however, these researches are of value, as nese 
show the liability to error and the amount of error possible. 
It is worthy of remark that the spontaneously precipitated alumina is is 
no longer gelatinous, but granular and Jess soluble in acids. 
G.C.S. 
_ 6, Action of Perchlorid of Phasphowel = ow Substances ; by 
Ave. Canours, (Comptes Rendus, eriseree 6.)—The perchlorid has 
no effect upon carbo-hydrogens, such as benzine and retinaphtha, but 
the hydrate of phenyle and anisol (differing from the former by the ad- 
ition of two equivalents of oxygen) are sear attacked, and form 
new compounds. The alcohols are known to produce chlorid, when 
treated with ee of phosphorus—by nt elimination of O2 with- 
ent, and by the substitution of Cl for H. The action upon 
