188 
Scientific Intelligence. 
from the 10th to the 8th, and sometimes to the 4th of an inch 
in length. The charcoal of the negative pole, on the contrary, 
was diminished, and a circle-shaped cavity was formed at the end 
of it, as if the matter had been actually transferred to the posi- 
tive pole, by a current flowing from the negative to the positive 
pole. From various experiments, Professor Silliman concludes, 
u that there is a current from the negative to the positive pole % 
and that carbon is actually transferred by it in that direction 
probably in the state of vapour. 
Upon examining with a microscope the projecting point of the 
positive pole, it exhibited decisive indications of having under- 
gone a real fusion. It presented a mamillated appearance, and 
its form was that of an aggregation of small spheres. Its sur- 
face was smooth and glossy, as if covered with a varnish. Its 
lustre was metallic, and it had entirely lost the fibrous appear- 
ance. It resembled brown haematite. The pores of the charcoal 
had all disappeared, and the matter had become sensibly harder 
and heavier. —Silliman’s Journal , vol, v. p. 108, — 112. 
16. Crystallisation under Pressure. — By means of a power- 
ful machine, by which a pressure of 1400 atmospheres may be 
obtained, Mr Perkins has, we learn, made several very import- 
ant discoveries respecting the crystallisation of sea-water and 
other solutions under this pressure. His discoveries have been 
communicated to the Boyal Society of London. 
17. Ammonia in Lava. — Professor Gmelin of Tubingen is 
said to have discovered in clinkstone lava ammonia, which is 
disengaged by distillation. He also found it in columnar ba- 
salt. 
18. Test for Barytes and Strontian. — In order to distinguish 
these earths, make a solution of either, by nitric, muriatic, or 
some other acid, which will form a soluble salt with it. Add 
solution of sulphate of soda in excess, filter and then test the 
clear fluid by subcarbonate of potash. If any precipitate falls 
down, the earth is strontian, but if the fluid remain clear, it is 
barytes. 
19. Analysis of Tabular Spar from Lake Champlain. — The 
following is the analysis of this mineral by M. H. Seybert of 
Philadelphia. Specific gravity 2.884. 
