RESULTS OF PHYSICAL AND CHEMICAL INVESTIGATIONS. 
119 
may change to ripples, and ripples to waves, magnitude may be substituted for 
number, and number for magnitude, asteroids may aggregate to suns, suns re¬ 
solve themselves into florae and faunae, and florae and faunae melt in air,—the 
flux of power is eternally the same. 
kk It rolls in music through the ages, and terrestrial energy, the manifestations 
of life, as well as the display of phenomena, are but the modulations of its 
rhythm.” 
26, St. George's Place , Hyde Parle Corner. 
REPORT OF THE 
RESULTS OF PHYSICAL AND CHEMICAL INVESTIGATIONS, 
AND OF THE 
APPLICATIONS OF PHYSICS AND CHEMISTRY IN THE ARTS. 
The [Detection of Arsenic in Copper. —Dr. Odling gives in the‘Journal of 
the Chemical Society ’ the following simple and efficient means for recognising minute 
traces of arsenic in the metallic copper intended to be used in Reinsch’s test. He con¬ 
ceives that as even in the most satisfactory performance of this test there is always 
some, although but an extremely small quantity of the copper dissolved, and as com¬ 
mercial copper is rarely quite free from arsenic, and sometimes contains a very notable 
proportion thereof, it is important that the copper to be used in medico-legal researches 
should be specially tested as to its purity. 
But as in the ordinary mode of experimenting by Reinsch’s process the amount of 
metal dissolved is scarcely appreciable, it is quite unnecessary to submit any considerable 
quantity of it to examination. If a solution of four or five grains of the copper does not 
yield any evidence of arsenic, it is quite pure enough for the purpose, even though a 
little arsenic should be recoguised in the solution of a larger quantity. 
As a means of detecting traces of arsenic in copper, the author believes that the 
following process is superior to any hitherto proposed in conjoint delicacy and rapidity 
of operation :— 
A few grains of the copper, cut into fine pieces, are placed in a small tube-retort with 
an excess of hydrochloric acid and so much ferric hydrate or chloride as contains a 
quantity of iron about double the weight of the copper to be acted upon. The mixture 
is then distilled to dryness, some care being taken at the last to prevent spurting. The 
whole of the copper is in this way quickly dissolved, and any arsenic originally contained 
in it carried over in the form of chloride of arsenic, which may be condensed in a little 
water with the excess of aqueous hydrochloric acid. The resulting distillate is then 
tested for the presence of arsenic, by treating it with sulphuretted hydrogen, or, pre¬ 
ferably, by boiling in it a fresh piece of clean copper foil or gauze. In some cases, the 
residue left in the retort may be treated with a little fresh hydrochloric acid, again dis¬ 
tilled to dryness, and the distillate collected and tested along with that first produced. 
Most oxygenants other than ferric chloride are objectionable, as by their reaction with 
hydrochloric acid they give rise to free chlorine, which passes over with the distillate, 
and renders it unfit for being immediately tested either with sulphuretted hydrogen or 
fresh copper. Cupric oxide or chloride, on the other hand, is scarcely active enough for 
the purpose ; while the dissolution of copper in hydrochloric acid brought about by mere 
exposure to the air is extremely tedious. 
It may be as well to add that ferric chloride is rendered quite free from arsenic by 
evaporating it once or twice to dryness with excess of hydrochloric acid. 
Separation of Ktagnesia from Potash and Soda. —The means which have 
been hitherto adopted for effecting the separation of magnesia from the alkalies have 
been long and tedious. The only perfect precipitant for magnesia, that is to say phos¬ 
phoric acid, could not be employed for the purpose without involving a very troublesome 
method for the subsequent elimination of the excess of phosphoric acid. 
M. A. Reynoso has recently communicated to the French Academy a very elegant 
method of accomplishing this object, founded upon a reaction which he himself discovered 
