82 Modern Fireproof and Watertight Building Materials, 



mischievous system in force of running up dwelling-houses 

 which, from their great susceptibility to damp, are the 

 source of many dreadful diseases. 



In support of the theory here advanced I may, in con- 

 clusion, aptly quote the opinion of an eminent English 

 authority. Mr. Chad wick, Commissioner of the Inter- 

 national Exhibition at Paris, in a report to the British 

 Government thus expresses himself: — "There is yet 

 another reason why the construction of walls in common 

 brick or soft stone should be abandoned, namely, from the 

 facility with which these materials absorb and retain 

 moisture. The brick ordinarily in use in England is. 

 capable of absorbing 1 lb. weight of water. Thus a small 

 cottage having walls one brick in thickness will be com- 

 posed of about 12,000 bricks. These afford the united 

 capacity of absorbing 1500 gallons, equal to 6000 quarts or 

 6 1 tons of water, which in its turn will require 3 tons full 

 measure of fuel to evaporate." 



As it will be impossible to abandon bricks altogether in 

 favour of concrete buildings, which Mr. Chadwick has in 

 view, we should at least employ methods by which the 

 dangers of dampness can be either prevented or reduced to 

 a minimum. 



APPENDIX. 



In order to make this paper more useful for the pro- 

 fessional Engineer and Architect, I thought it advisable to 

 add a table of the bearing strength of the various Traeger- 

 wellblech plates now in use. 



The tests, of which the following data are the results, were- 

 carried out under the superintendence of Royal Engineers 

 and Architects in Berlin: 



I. Bridge Plate. 



Plate No. 14, 3 feet long, tested by hydraulic pressure. 

 22J tons caused a bending of 3" 

 28J „ „ „ of ' 



29 „ „ breaking. 



II. Flooring Plate. 

 A curved Traegerwellblech plate, No. 2, 11 feet span, 1' 2" 

 rise. The plate broke when loaden with 2800 lbs. of pig 

 iron per superficial foot. 



