162 Ransome’s Patent Concrete Stone. | April, 
objection, is, nevertheless, more open to the first. In the moist 
process calcined flints were ground to a fine powder, and then min- 
gled with a large excess of alkali, either potash or soda; and this 
mixture boiled for a considerable length of time, when a thin, rather 
sweetish fluid formed, which was a solution of silicate of soda, when 
that alkali was used. As already stated, the disadvantages attending 
this process are the large excess of alkali which it requires, the 
tediousness of the operation, thinness of the solution, and lastly, 
the expense of calcining and pulverizing the flimts.”* 
The great desideratum now was to devise some method whereby 
a solution of silicate of soda might be obtained of sufficient con- 
sistency for his purpose, and at such a price as to render it available 
for general use. Whilst lying in bed one night, the idea suddenly 
flashed across his mind that if he subjected flint-stones in a solution 
of caustic alkali to heat in a boiler under high pressure, he might be 
able to reduce them to the desired state. Forcibly impressed with 
the idea that he had at last hit upon the right means to his end, he 
jumped out of bed, and having called his laboratory boy to his as- 
sistance, he took an old boiler belonging to a model steam-engine, 
and having fitted on to it a safety valve and a small cock whereby 
to draw off the liquid at intervals to test it, he filled the boiler with 
flints and a small quantity of caustic soda and water. He now 
urged the fire,and from time to time drew off small quantities of 
the liquid, which, in spite of all endeavours, continued as thin as at 
first. The pressure, perhaps, was not sufficient, so he tied down 
the safety valve, and continued to urge the fire until, to his dismay, 
the boiler began to get red-hot. Thinking now that his experiment 
was at an end—that all the liquid in the boiler had evaporated, and 
probably nothing remained within it but the hard flint-stones as 
they bad at first been placed there—he began to yield to despair, 
for but a short time yet remained before he must file his com- 
plete specification. Taking hold of the boiler with a long pair of 
tongs, he threw it into a cistern of water which stood close by, 
and, as might have been expected, the boiler at once flew to pieces. 
Desirous now of obtaining some rest after the toil and excitement of 
the preceding hours, he was going into the house to retire again to 
bed, when, on passing the cistern, he looked in upon the fragments 
of the boiler, which, to his astonishment, were coated internally 
with a white waxy substance, and at the bottom of the cistern lay a 
glassy syrupy mass. On trying to separate this hard substance from 
the shell of the boiler he found that the part of it in immediate 
contact with the iron was hard as the natural flint from which it 
had been made. ‘Thus then, when on the brink of despair at the 
supposed failure of his endeavours, Mr. Ransome discovered that, 
not only could he reduce his flints to an almost liquid consistency, 
* «The Engineer,’ December 5, 1856. 
