88 
rorOLAIl SCIENCE EEVIEW. 
inonts recorded, to le the portion ahsoihed. Thus a screen of chlorine was 
found to be most ell'ectual in depriving the beam of the electric lamp of its 
power of exploding a mixture of chlorine and hydrogen. For desciiptions 
of the symmetrical and fantastic forms and motions of the clouds of 
decomposed vapours, we are compelled, by their length, to refer the reader 
to the memoir itself, in the Pi'occeduujs of the Itoijcd Societ]/, No. 105. 
On the Estimation of Phosphorus in Cast Iron. — A process for the estima- 
tion of pliosphorus in cast iron is given by M. Tantin in the Comptes-Pendus, 
similar in principle to the excellent method for the estimation of sulphur. 
Instead of attempting to oxidise the phosphorus to the state of phosphoric 
acid, whereby some of it, by escaping oxidation, is not determined, he pro- 
ceeds to separate it from the iron in the form of pliosphoretted hydrogen, 
wliich he aflirms can be coinpletely accomplished by the action of hydro- 
chloric acid. First passing the gas evolved through a solution of potash, to 
remove the sulphuretted hydrogen, he transmits it to a solution of silver 
nitrate, which precipitates the phosphorus as an insoluble phosphide, and 
converts the arsenetted hydrogen, always present, into the soluble arsenite of 
silver. The precipitated and Avashed silver phosphide is then oxidised and 
converted into phosphoric acid and chloride of silver by aqua regia, and the 
phosphorus weighed as magnesian phosphate in the usual manner. 
Electro-capillary Phenomena . — M. Becquerel has added a sixth to his 
previous memoirs on the chemical reactions which occur between liquids 
communicating with each other through the capillary spaces of cracked 
glass, layers of fine sand, parchment-paper, and other porous septa. In 
this memoir {Comptes-Pendus, Nov. 30) he describes the formation of 
crystallised hydrates of chromium, aluminum, silicates, carbonates, t&c. For 
example, by placing chromium chloride in solution on one side of a parch- 
ment-paper septum, and potassium aluminate on the other, he obtained 
crystals of hydrated chromium oxide and crystalline plates of hydrate of 
alumina. M. Becquerel believes that he has proved that the infinitely thin 
layer of liquid adhering to the walls of capillary spaces separating two 
different liquids, acts as a solid conductor to the two electricities set free 
during the chemical reaction of the liquids on each other in these spaces. 
Tliere is thus formed an electro-chemical couple, giving rise to a current, 
called by M. Becquerel clectro-capi'lary, to recall its origin, Avhich has- 
sufficient energy to reduce solutions of metals to the metallic state, and to 
produce, with the concunence of other causes, a large number of com- 
fiinations end decompositions. In this couple the layer of liquid adhering 
to the walls of the capillary cavities, which acts as the solid conductor of 
ordinary arrangements, has a molecular constitution differing from that of 
the adjacent liquid not submitted to the attractive action of these walls. 
M. d(‘ la Hive (in the liihliothl (pie Univ. de Ceneve and I'hil. May. Dec.) 
supposes that, in>tead of the liquid enclosed in the capillary space acting as 
a solid conductor of electricity, the observed phenomena are the effects of 
chemical action alone, more or le.ss modified by the fact that the .space is 
caj)illarA', and, in particular, that the action can only take place on a small 
number of molecules at a time, and succes.‘'ively, inste.ad of acting on the 
wlioh* of the two solutions at once. It is very probable, says 1\I. do la liive, 
that the chemical action is modified by the so-called molecular attraction 
