496 Proceedings. 



with the non-inflammable concrete on both sides. Well, it had been 

 said, " But surely such a method of construction would be precluded by 

 the expense." But no ; for one of the great beauties of this method was 

 that it was more economical than building with brick or stone or solid 

 concrete. His only objection to the method was the weight of the con- 

 crete. Happily this objection had been overcome in a higlily satisfactory 

 manner by Mr. Donaldson. A friend of Mr. Lascelles, the patentee of 

 the system of building with concrete slabs in England— adopted, by the 

 way, principally upon the score of economy, earthquakes not being usual 

 in England — Mr. Donaldson, upon arriving here, set to work to improve 

 upon Lascelles's system of manufacturing the concrete. By using pumice- 

 sand with the best Portland cement, a concrete is produced which is of 

 a much better natural colour, and, what is of greater importance, much 

 lighter in weight than those made in the ordinary way. According to the 

 proportion of cement used different degrees of hardness can be obtained, 

 from that equal to Oamaru stone to granite. Thus, then, no obstacle so 

 far as material, method of construction, and expense would stand in the 

 way of this method for erecting both earthquake- and fire-proof buildings 

 being adopted. What obstacle remained, then ? Really none. But, as 

 Mr. Higginson pointed out, architects are very much handicapped. In 

 the first place, the City Council's by-laws merely provide against fire, 

 by compelling the use of brick and stone, or solid concrete walls erected 

 in the ordinary way, in the business quarters of the town ; and he con- 

 sidered that the Council should be asked to permit the method of build- 

 ing in the manner pointed out. In the second place, those intending to 

 build were afraid to go out of the beaten track, and architects were afraid 

 to push home to their clients any such vital changes. 



ilr. Donaldson also asked permission to speak, and said the pro- 

 blem of building houses sufficiently fire-proof, wind-proof, damp-proof, 

 and earthquake-proof requires very careful consideration. In the first 

 place, heavy materials such as stone and brick are more easily overturned 

 than wooden structures, because if thrown slightly out of the perpen- 

 dicular by an earthquake-shock their weight tends directly to bring them 

 down, whereas a wooden structure with a properly-joined framework 

 would bear a very considerable oscillation without any great effect being 

 produced. But the objections to wooden buildings are, — 



(1.) They are dangerous in case of fire. 



(2.) They are not wind- or vermin-proof. 



(3.) They rapidly deteriorate after being up a few years, and are 

 too expensive to keep in repair. 

 The question therefore naturally arises : Can houses be erected with the 

 tensile strength of a wooden framework, with a light yet strong material 

 for the walls, proof against earthquake-shocks, as near as possible fire- 

 proof, at the same time to exclude damp and wind, and offer great resist- 

 ance to wear and tear ? The method of construction used in iron-ship 

 building answers all these requirements ; but to build houses of thick 

 plates of iron fastened on an iron framework would be very expensive, 

 and the iron plates, being rapid conductors of heat and cold, would make 

 such houses very uncomfortable. With a view to meet the requirements 

 of the case, he had patented a concrete slab, made of a mixture of strong 

 cement, pumice-sand, and sometimes gas-coke. This meets all the re- 

 quirements. Samples of this material he exhibited. It has the follow- 

 ing advantages : — 



(1.) Unlike ordinary concrete, it is homogeneous, can be cut with a 

 chisel or saw, can bear holes being drilled in it, and is per- 

 fectly uniform in strength. 



(2.) It is fireproof. The slabs can be heated to a red heat without 

 injury. 



(3.) These slabs are made generally lin. to l|in. thick, and can be 

 fastened to the studs in an ordinary wooden framework by 



