llO ANNUAL OF SCIENTIFIC DISCOVERY. * 



Thf material consists of one part of Portland cement to 8 parts 

 of coarse <^ravel. The cement and ofravel are first well mixed 

 together in a dry state, and when this is done it is damped by 

 means of a lar*;;e waterinj^-pot, and again mixed by a pronged 

 dra":, such as is used for dra«2:j2:inf!: dun<j: out of a cart, until the en- 

 tire iieap has been wetted and mixed togetlier. It is then put in 

 iron or zinc pails, and poured into tlie I'rame, where it is levelled 

 by men stationed for the purpose. In order to save concrete, 

 large lumps of stones or brickbats are put into the centre of the 

 wall, and covered over and about with concrete. Frost does not 

 atfect the concrete after it has once set, which, with good cement, 

 will be in about 5 or 6 hours. Nor do heavy rains appear to in- 

 jure it in the slightest degree, though they may chance to fall 

 ere the concrete has hardened. The walls can be made straight 

 and even as it is possible for walls to be, and the corners as 

 sharp and neat as if they had been formed of the most carefully 

 dressed stone. 



Concrete makes excellent floors, and the walls and floors are 

 quite impervious to vermin of all kinds, and also to wet. Many 

 kinds of building-bricks will absorb water; hence brick houses, 

 when the walls are saturated with water, are cold. This is not 

 the case with houses constructed of concrete, as it is non-absorb- 

 ent of' moisture, and such houses must be, therefore, more 

 healthy. 



This novel mode of buildin;!: houses has excited ffreat interest 

 in the neighborhood of llunnamoat, Ireland, and the proceedings 

 have daily attracted numljcrs of people from all parts. 



While concrete may Ije used in constructing buildings of every 

 description, it is peculiarly adapted, from its cheai)ness, for the 

 construction of cottaijes for laborers, and also for farm buildinirs. 

 Its cost is not more than half that of brick-work ; almost any ma- 

 terial can be used along with the cement, and, as we have already 

 shown, the most ordinary class of country laborers are quite com- 

 petent to carry out the details of the system. With rclerence to 

 its adaptability for large buildings, we may mention that a ware- 

 house 70 feet long, 50 feet wide, and GO feet high, 5 stories in all, 

 has been erected on Mr. TalPs svslem for Mr. II. Goodwin, 

 Great Guildford Street, Southwark, England, and that gentleman 

 testifies in the warmest terms to its fatislactory character, and is 

 m:iking arrangements at the present time for the construction of 

 another simihtr buiidinsj. The warehouse alreadv erected has at- 

 tracted universal admiration from the practical and scientific gen- 

 tlemen who witnessed its erection. 



The chief element of success, when the cement is of good 

 quality, seems to be the thorough mixture of the dry materials, 

 to Secure uniform strength. 



ENGINEERING UNDER GROUND. 



We learn from the •* Artisan," London, that a new length of the 

 line of the undergnjund railroad of that city has been completed 



