432 NOTES AND ABSTRACTS IN CHEMISTRY AND PHARMACY. 
Sublimed purpurogalline occurs in the form of garnet-red needles, more co¬ 
loured and more brilliant than the crystals of alizarine. Its sublimation is 
accompanied by a slight decomposition, but this is easily avoided by projecting 
the substance on a bath of mercury heated a little above 200° C. It is slightly 
soluble in water, more soluble in alcohol, ether, and benzol. Sulphuric acid 
dissolves it, forming a compound, crystallizing in crimson-red needles, decom¬ 
posed by water. Nitric acid destroys it, yielding picric acid. The alkalies 
give with it a fine blue colour, changiug to green and yellow. 
Crystallized Subacetate of Leach 
M. Jeannel gives the following process for preparing subacetate of lead in 
crystals:— 
Crystallized Acetate of Lead . . 6 parts 
Pure Oxide of Lead . ... 2 ,, 
Water.1 „ 
Triturate the salt and the oxide together, then add the water. Heat the mix¬ 
ture in a porcelain capsule, stirring gently with a glass rod. Fusion takes 
place at about 65°, and ebullition at 102° C. After boiling two or three 
minutes, the liquid is filtered through paper in a funnel heated by a water-bath. 
The subacetate of lead thus obtained crystallizes on cooling in silky tufts, leav¬ 
ing a very small quantity of mother liquor. 
Reactions of Morphia and Papaverine. 
MM. Hofman and Schroff indicate a means of distinguishing between these 
two alkaloids, morphia and papaverine. The double iodide of potassium and 
cadmium gives with papaverine a small white precipitate, which collects into 
pearly scales; while with morphia, even in very dilute solutions, it gives fine 
crystalline needles, which are very characteristic. By a microscopic examina¬ 
tion, these two precipitates may be easily distinguished. 
Petrified Concrete. 
Some works have recently been established in the neighbourhood of Victoria 
Park for the manufacture of artificial stone by a new process. It has been 
known for some time that Portland cement, or any concrete containing lime, 
can be rendered extremely hard by immersion in a solution of silicate of soda. 
Under these circumstances, the silica is absorbed by the lime, and the cement 
thereby converted into a true stone. But the cost of the silicate of soda has 
hitherto rendered such a process too expensive for general application. The 
proprietor of the works we refer to has overcome this obstacle in a most inge¬ 
nious manner. Beneath the chalk beds of Surrey, in the neighbourhood of 
Farnham, there exists a plentiful deposit of a soft stone, containing 25 per cent, 
of silica, in a condition in which it is soluble in a cold solution of caustic soda. 
This material the inventor grinds up and diffuses through the bath of silicate of 
soda, containing the concrete to be petrified. The lime, removing silica from 
the solution, liberates caustic soda, which dissolves fresh silica from the Farn¬ 
ham stone. The process thus becomes a continuous one. The soda acts as a 
carrier of silica from the stone to the cement. By due care, the solution of sili¬ 
cate of soda may be maintained of constant strength, and is therefore capable of 
performing an almost indefinite amount of work. The expense of the silicate of 
soda being once defrayed, the cost of petrifying the concrete is simply the value 
of the Farnham stone, and the labour of applying it. No heat is required in 
any part of the process, and the work is therefore very simple. 
So cheaply can this new material be produced, that it is proposed to apply it to 
the construction of paving-stones. In this case granite chippings are w r orked up 
