258 Scientific Intelligence. 
iron into a protosalt by the addition of ‘sulphite of soda, and boil the 
solution to expel the excess of sulphurous acid; it is important that 
none of this latter substance should be present when the next step in 
the operation is made, this can always be ensured by having an excess 
of hydrochloric acid. 3. Add, with precaution, froma graduated yes- 
sel a solution of the permanganate of potash, the strength of which is 
known, and by reading off the number of divisions consumed, before 
any pink tint appears. in the solution of iron, the amount of this lat- 
ter metal present is calculated ; in this part of fee ‘process; it is neces- 
sary to have the solution very dilute. 
The manner of preparing this test liquid is as follows.—The chame 
leon mineral is first prepared as proposed by Gregory ; by fusing siacthe 
er chlorate of potash, hydrate of potash, and peroxide of manganese 
in the proportion of one atom of the first, three of the second, and 
three of the third. The fused mass is treated with water, so as to ob- 
tain a concentrated solution to which is afterwards added dilute nitric 
acid until it acquires a violet color ;—the solution is now filtered and 
ready for use. To obtain it of the proper strength, dissolve one 
gramme of pure iron in hydrochloric acid, dilute with about one quart 
of water, and add from a graduated vessel the solution of chameleon 
mineral, until the pink color appears; noting the number of divisions 
of the solution consumed, we are then in possession of all the data ne- 
cessary for future R 
None of the substances ouailintein with the ores of iron interfere 5 
with the Soemenis of the result, except copper and arsenic, both of :| 
which are got rid of by adding a piece of zinc to the solution of the “4 
ore in hydrochloric acid. before it is caus with the sulphite of soda. 
Je 
. 
7. On the Quantisasios Dete>méination of Mer dire ; ; by E. Mitton, 
(Annales de Chem. et de Phys., 1846, and Chem. Gaz., March, 1846. ) 
—A long glass tube, such as is used in organic winged is first con- 
tracted near to one of its extremities, and at the very extremity drawn 
out to a. point and curved upwards ; the space between the two contrac- : 
tions being from three to four inches. A small quantity of asbestus is : 
introduced into the tube next to the point first contracted, and upon this 
are placed fragments of caustic lime to the extent of six or eight inches; 
the mercurial compound is next introduced varying from. 15 to 60 grains, 
and then the tube is filled with caustic lime similar to the other. In the” 
analysis of nitrate of mercury, the lime should:be replaced by metallic 
— The tube is now placed in the furnace used for organic 
- A-current of pure hydrogen: (purified by passing the dry 
ee sktnecapor-totnias heated to to.redness) i is made to enter at the un- 
contract 1 xt ni id th heat a ied exactly as in organic anal+ . 
pee Syren. 
