1868. | Chemistry. 391 
letters the author adopts pictorial symbols by which to represent 
the elements, and arranges them in a geometrical pattern to con- 
struct the compounds formed by their union. In the discussion 
which followed the reading of this paper, Drs. Atkinson, Russell, 
Stevenson, and Odling spoke briefly, and, in a general sense, 
adversely, as to the desirability of introducing the system to the 
notice of the student. Dr. J. H. Gladstone followed with a paper “On 
the Tetraphosphoric Amides,” compounds produced by the action 
of water on the amidated oxychlorides of phosphorus; and the pro- 
ceedings concluded with a paper by Mr. Carter Bell “On the 
Solubility and Crystallization of Plumbic Chloride in Water, and in 
Water containing various proportions of Hydrochloric Acid.” The 
author finds the degree of solubility in pure water to be about 
1 part in 121 parts, instead of in 135. The solubility in hydro- 
chloric acid decreases up to a certain point, when the curve com- 
mences to ascend. 
The meeting on May 7th was very fully attended, and many dis- 
tinguished visitors were present to hear Mr. C. W. Siemens, F.R.S., 
deliver a lecture “On the Regenerative Gas Furnace as applied to 
the production of Cast Steel.” The following is a very condensed 
account of this important lecture; and it is to be regretted that 
the many demands upon our space will not permit of its being given 
more fully. The lecturer commenced by briefly sketching the pro- 
perties and modes of preparation of cast steel, which he defined as 
a compound of iron and carbon possessing the remarkable property 
of becoming exceedingly hard when heated and suddenly cooled. 
Steel containing 1-4 per cent of carbon partakes of the character of 
white cast iron, and below 0:3 per cent. the metal is incapable of 
being hardened. The presence of manganese improves the quality 
of steel, apart from its function in removing sulphur and other im- 
purities. Tungsten, in quantities of about two per cent., has the 
remarkable property of increasing the power which steel possesses 
of retaining magnetism when hardened. This property of tungsten 
was illustrated in the lecture-room by a small permanent magnet of 
horse-shoe form, which supported twenty times its own weight from 
the armature; the celebrated Haarlem magnet being incapable of 
lifting a weight more than thirteen times heavier than itself. The 
principle of Mr. Siemens’s plan of heating is already well known. 
The fuel is heated upon an inclined fire-grate, where it undergoes a 
kind of slow combustion which results in the formation of carbonic 
oxide ; this inflammable gas is then conducted from the “producer” 
to the hearth or working platform of the furnace, where it meets a 
current of air already raised to a high temperature, which enables 
it to burn with great intensity ; and the excess of thermal power, 
instead of being allowed to pass direct into the chimney and thus 
become wasted, is forced to traverse an intricate structure of brick- 
VOL. V. 25 
