1872.] Chemistry. 279 
CHEMISTRY. 
Dr. S. Meurier states that when a piece of meteoric iron is fixed to the 
positive pole of a Bunsen battery, the other pole being a piece of silver, and 
the electrodes are placed in an aqueous solution of bisulphate of potassa, and 
contact made, there will appear on theiron an iridescent colouration similar to 
the colouration brought about by heating the polished iron; if no contact 
takes place, there is produced upon the iron a figure similar to that which 
acids produce, but by this method it is more readily and more neatly 
brought out. 
Professor J. Lawrence Smith has given a detailed description and analyses 
of the large masses of meteoric iron in North Mexico, with the description 
of a new mass—the San Gregorio Meteorite. This immense mass of meteoric 
iron is situated on the western border of the Mexican desert. Its shape 
bears some likeness to that of a blacksmith’s anvil. Its greatest length is 
6 feet 6 inches; it is 5 feet 6 inches high, and 4 feet thick at its base. On 
one part of its surface ‘‘ 1821” is cut with a chisel, and above this date is 
the following inscription :—‘‘ Solo dios con un poder este fierro destruera, por 
que el en mondo non habra quien lo puedo deschacer”’ (Only gods can have 
the power to break up this mass of iron, for there is no body on earth who 
can break it to pieces). The weight of this mass is nearly 5 tons; it lies near 
to the spot where it has fallen, but nothing is further known of its history. 
A small detached specimen of this stone, which is of the softer meteoric 
iron (sp. gr. = 7°84) gives the following chemical results:—Iron, g5:o1; 
nickel, 4°22; cobalt, 0°51; copper, minute traces; phosphorus, 008. The 
Mexican desert has an extension of 400 miles from east to west, and 500 miles 
from north to south, equal to an area of 200,000 square miles. The United 
Kingdom has an area of 121,518 square miles. 
In works on chemistry, indigotine (pure indigo blue) is described as a body 
insoluble in water, alcohol, ether, fatty and essential oils, and dilute acids 
and alkalies ; yet strong and boiling alcohol, and even somewhat more so 
methylic alcohol (not methylated spirit), dissolve enough indigotine to become 
blue-coloured, but, on cooling, the greater part of the dissolved substance is 
thrown down again. By experimenting with phenic acid, M. C. Méhu has 
found that this substance is an excellent solvent for indigotine, which may be 
extracted readily and in pure state from indigo, care being taken to wash this 
latter substance first with water, then with dilute hydrochloric acid, and next 
several times with boiling alcohol: in order to prevent the solidification of 
phenic acid on cooling (heat has to be applied to dissolve the indigotine), 
some camphor may be added to it. With 500 grms. of phenic acid, 2 grms. 
of indigotine may be readily obtained in one operation, and in very pure 
well-defined crystals. Indigotine is also soluble, to some extent, in phenic 
acid when cold, this solution exhibiting a very deep purple colour. 
Mr. C. Bullock has published the results of a few experiments to solve 
approximatively*the question, ‘* What amount of acids or alkalies is necessary 
to give a distin@ change of colour to the test-paper?”’ Blue litmus-paper 
should be distin@ly blue, but not a deep shade, in colour; the directions given 
by Dr. Fresenius in his ‘‘ Qualitative Analysis” will afford a sensitive paper. 
When carefully made it atfords the reaction with one drop of acetic acid at 
30 per cent in the following quantities of water:—In 4 ozs., it turns red 
immediately ; in 6 ozs., completely red in half a minute; in 10 ozs., changes 
on the edge in one-fourth minute, and is completely reddened in 1 minute; in 
13 Ozs., it is completely red in r3} minutes, and remains red when dry; in 
16 ozs. of water the limit of distin@ reaction is found. Reddened litmus 
should havea purple-red colour, and the paper when dry a distinc red colour 
free from blue. With 1 grain of anhydrous carbonate of soda in 32 ozs. of 
water the paper turns blue in 1 minute; in 56 ozs., in 3 minutes; in 64 ozs., 
in 4 minutes; in 80 uzs., in 7 minutes; in 160 ozs. of water the limit of dis- 
tin@ reaction is found; the blue shade can be seen before the colour is 
dissolved from the paper. In these experiments the paper was submerged in 
the liquid. 
