TABLE B.-continued.

Comparative Table of Messrs. COIGNET'S & RANSOME's with other Materials under Pressure.

Table shewing the strength under pressure at different ages of WHEEBLE'S Patent Concrete Stone (Reading Abbey).

Table shewing the strength under pressure at different ages of BODMER'S Patent Compressed

Cracked. Crushed. Cracked. Crushed. Cracked. Crushed. Cracked. Crushed. Cracked. Crushed.
Tons. Tons. Tons. Tons. Tons. Tons. Tons. Tons. Tons. Tons.
5.4
52.02
under a Ton
3.77
7.8
12.35 6.95

1.4

2.4

3.9

20.0

m

m. The ram at this point being leaky the reading is doubtful.

GG 2

TABLE D.

Table shewing the results under pressure of Cubes 2′′ 4′′ and 6′′ in height, by their Base.

TABLE F.

Table shewing Tensile Strength, form suggested by MR. DINES.

SOME OBSERVATIONS UPON EXPERIMENTS ON ARTIFICIAL STONE, &c. UPON READING THE REPORT OF THE COMMITTEE THEREON.

By OCTAVIUS HANSARD, Fellow.

Read at the Ordinary General Meeting of the Royal Institute of British Architects, May 30, 1864.

UPON the appointment of your Committee last year, for the purpose of making experiments on artificial stone, I was requested by them to conduct the enquiries and superintend the investigation of the processes submitted; and therefore deem it right, upon the presentation of our Report this evening, to offer a few remarks, showing how we proceeded upon those investigations, and some observations upon the results. I regret that we had not more responses to our invitation to patentees; but probably that was owing to the conditions that were laid down by the Council, that we were to enter solely upon the enquiry as to artificial stone. After applying to several firms for the use of their yards to carry on our experiments, we succeeded in gaining permission from Mr. Dines to use his; and he subsequently placed his men, materials, and his hydraulic machine, at our disposal at all times. The gentlemen who had answered to our advertisement were then invited to submit their processes.

In order to test the cohesive strength of the respective materials submitted to us, and by comparison draw some conclusions, we had wooden moulds made, cubes of 4-inch sides. Mr. Dines provided the materials, which were mixed before us, except Messrs. Bodmer's specimens, and some of Messrs. Ransome and Wheeble's; and these were carefully marked, and placed exposed or otherwise, until the time arrived for testing them. The Committee represented to those gentlemen who did not prepare samples before them, that a guarantee as to the truth of their statements would be accepted; but whatever the results, this fact would be made known.

Bodmer's Patent Compressed Stone Bricks, although not absolutely coming under the denomination of artificial stone, were seemingly of so interesting a character that the Committee accepted and tested their strength at various ages. Table C shows you the results.

Mr. Wheeble sent several bricks of the Reading Abbey Concrete Stone, and specimens, 4-inch cubes and 9-inch bricks in our own moulds, were made before us. From Table C, of results, you may perceive how little they are adapted to resist crushing weight, their composition being uncertain; their chief ingredient often being large stones and granite, at other times small gravel. The cubes noted e, e, three weeks' old, not composed of Bridgewater lime, crushed at 2:0 tons, or 135 of a ton on the square inch; whilst the weakest of Ransome's, at three days, bore 6·05 tons, or 378 of a ton on the square inch; and Coignet's, at four weeks, 3.8 tons, or 237 of a ton on the square inch; and in Wheeble's there seemed little cohesion as when crushed the lime fell through almost pure.

Mr. Charles Martin Westmacott's process was described on the evening last year, when Mr. Kerr read his paper. He claims, chiefly, the mixing of any carbonate of lime with lime, cements, or with the combination of lime and cements, preparing his mixture in different proportions, and sending it out as lime, the sand being added in the usual manner; his principle being to have always a much larger proportion of insoluble to soluble matter. It hardens by age and atmospheric influences, and is suitable both for internal and external stucco. This latter is composed of one part slaked lime to two of chalk, and can be used either as stucco or as common mortar; or if mixed with cement, as a good cement mortar. If for internal or quick stucco, the combination is one of chalk and two of unslaked lime, mixed pure with sand, before adding water; but for sending any distance, or for keeping, other materials are added.

H H