392 Chronicles of Science. (July; 
work, which absorbs so much heat that the escaping gaseous pro- 
ducts of combustion rarely indicate a temperature above 300° F. 
At a suitable stage of the operation the gas-valves are reversed, and 
both carbonic oxide gas and air are forced to traverse these heated brick 
chambers in a contrary direction, so that they may in turn become 
the recipients of that heat which in ordinary constructions of furnaces 
would have been lost. The ashes and clinkers are in this way 
entirely separated from the region of manipulation, and are removed 
from the grate at intervals of one or two days. The author esti- 
mates the temperature produced by the combustion of the gas and 
air to be 1,000° to 1,300° F. when they are cold to begin with; but 
when they have been separately passed through the regenerator and 
thereby raised to a temperature of, say, 1,000° F. beforehand, the 
temperature of their combustion will be, say, 2,000°. The surplus 
heat from this will then raise the temperature of the regenerator 
still higher, and the gas and air will consequently attain a higher 
degree of heat before they unite. The platform of heat, so to speak, 
on which they commence their combustion, will be raised each time, 
until practically there is no limit to the degree of temperature which 
may be attained in this manner—the whole mass of the furnace, 
with its contents, having occasionally been melted down into one 
mass. ‘The special furnace which Mr. Siemens has erected at Bir- 
mingham for the direct production of steel from the ore, has a 
tunnel-head or cylindrical hopper, fed with iron ore and small coke, 
passing through and raised above the crown of the regenerative gas 
furnace; the lower part of this upright cylinder rests in a bath of 
molten pig-iron, which dissolves the reduced (spongy) iron as quickly 
as it is separated from the ore. A blast-pipe descends through the 
stack of ore, and the process is interrupted when the steel is ready 
for casting, after which the charge of pig must be renewed. Itisa 
very important point in connection with these furnaces, that the at- 
mosphere of them may be changed at will into an oxidizing, reducing, ~ 
or perfectly neutral condition, merely by altering the proportions of 
air and gas. After the delivery of this lecture, which was amply 
illustrated with experiments, specimens, and a series of diagrams and 
dissected models, an animated discussion followed, in which the 
President, Mr. Cowper, Professor Abel, Dr. Miller, Dr. B. H. Paul, 
Dr. Williamson, and Dr. Odling took part. 
On May 21st, Dr. Russell opened the proceedings by showing 
some experiments “On the Application of the Measurement of Gases 
to Quantitative Analysis.” The author considers the system of mea- 
suring to be more accurate than weighing in a variety of analytical 
operations wherein gases are evolved, and the results which he has 
obtained certainly corroborate this view. In the discussion which 
followed, Dr. Williamson said that as a rule the process of measuring 
was more accurate than weighing; for, whilst we could not weigh 
