436 
POPULAR SCIENCE REVIEW. 
Iron and Manganese in Steel by the Bessemer Process. — The 11 Chemical' 
News,” August 7, says, in its excellent summary, that carbon and phos- 
phorous are pronounced mutually exclusive, but either of them yields with 
iron an alloy possessing the properties of steel. The metallurgic company 
of Terre-Noire has achieved a result of great importance for the perfecta- 
tion of the Bessemer and Martin process by the introduction of solid blocks 
of an alloy of iron and manganese, containing 65 per cent, of the latter metal, 
and capable of being introduced into the converter in the last stage of the 
operation. 
Absorption of the Ammonia of the Atmosphere by Plants. — M. T. EL 
Schloesing says, “ Comptes rendus,” June 15, he experimented upon two^ 
tobacco-plants exposed to confined, but renewable, artificial atmospheres, 
prevented from coming in contact with the soil. To one of these atmospheres 
ammonia was regularly supplied in small known quantities. The plant ex- 
posed to this atmosphere was richer in nitrogen than the other in every part. 
The production of nicotine was not sensibly affected. 
GEOLOGY AND PALAEONTOLOGY. 
The Tenth Report on Kent’s Cavern was read by Mr. Pengelly, F.R.S., at 
the meeting of the British Association at Belfast. This cave contains four 
layers in ascending order — breccia, crystalline stalagmite, cave earth, and 
granular stalagmite. The work of exploration is still going on in the Cave 
of Inscriptions and Clinnick’s Gallery. The breccia has yielded a great 
number of implements, and bones in abundance have been found. One very 
fine implement was found near to the great boss of stalmagite, from which 
an inscription on its surface shows that the stalagmite has undergone no 
change during the last two-and-a-half centuries. Mr. Pengelly differs from 
Sir C. Lyell, inasmuch as the author holds the opinion that man came to 
England, not only when it was part of the continent, but men must have 
been in Devon at a much earlier period, when England was separated from 
the continent of Europe. In the discussion which ensued, Professor Geikie r 
of Edinburgh, doubted the conclusion that the author had arrived at — viz. 
that the men of Devon had looked upon the glaciers of the glacial period. 
Rev. Mr. Croskey and Professor Harkness took part in the discussion. — Mr. 
Pengelly, in reply, said he based his opinion regarding the early appearance 
of man on the remarkable absence of the hyena, which is so abundant in the 
cave earth. 
The Silicifed Pock of Lough Neagh. — Professor Hodges read an interest- 
ing paper on this subject before the British Association (Belfast), in 
which he said that analyses show that the water of Lough Neagh, in 
our time at least, possesses no peculiar qualities, and that the lapidifying 
material of the petrified wood is silicic acid and not oxide of iron. 
Coal (or Lignite') in the Cretaceous of Minnesota. — Professor H. Winchell,. 
in his report for 1873, announces the existence of coaly layers at several 
points in the cretaceous of Minnesota, especially in the banks of Crow Creek: 
