MECHANICS AND USEFUL ARTS. 109 



reduced, and an additional advantage is gained in the fact that, 

 from the facility with which it is worked, there exists but little 

 difference in the cost of the plainest and most elaborate patterns. 

 The work, when coated with paint suited to the purpose, may be 

 made to resemble cut stone work so closely as to deceive the eye 

 of any one not an expert ; and in like manner the interior of 

 buildings can be ornamented with zinc in imitation of stucco, or 

 embellished with elaborate mouldings at a small cost, which work 

 may be cleaned at any time without fear of injury. In the orna- 

 mentation of old buildings, which, if of cut stone, could only be 

 accomplished by taking down the walls, zinc also plays a useful 

 part, as decorations may be put on without displacing any portion 

 of the structure. As a roofing material its value has become 

 generally acknowledged in Europe, and, in this country, is 

 rapidly acquiring an equally high reputation, particularly in the 

 construction of large buildings. When exposed to the influence 

 of the atmosphere, the oxidation that at once ensues, instead of 

 rapidly eating up the metal, soon forms a crust which hardens 

 and effectually protects the body of the covering from further 

 damage. 



The points which we have presented above in regard to orna- 

 mentation are simply those which seem most important in demon- 

 strating the value of zinc as a building material, and while we 

 do not by any means advocate its use generally in the place of 

 stone in ornamentation, where stone is plenty and cheap, yet we 

 wish, if possible, to overcome the prejudice which appears to 

 exist in many instances where the employment of zinc would be 

 more economical and equally appropriate. 



PROGRESS OF INVENTION ABROAD. 



Iii a paper read before the British Association for the Ad- 

 vancement of Science, Mr. J. W. Cooper, who has given much 

 attention to the Watering of Streets by Chemicals, states that 3 streets 

 in the city of Liverpool were watered with salts during the 

 month of July, 1869, with very favorable results, so much so 

 that the experiments were continued this year. It was difficult 

 to prove the economy resulting from the use of chloride over a 

 limited area ; and the Westminster Board of Works, after observ- 

 ing the effect produced at Whitehall and Knightsbridge, resolved 

 to extend the experiment throughout their entire district, com- 

 prising an area of 250,000 square yards. As soon as the area was 

 extended, the economy in labor and water was at once made 

 evident. By using 1| ton of chlorides per day, costing 3 15s., 

 the labor of 10 cart-horses and men, costing 4 10s. (at 9s. per 

 horse, cart, and man), can be dispensed with, and, consequently, 

 the quantity of water they would spread is saved also, namely, 

 350 loads of 250 gallons each, which, at lOd. per 1,000 gallons 

 (a fair average price for water in London) , would amount to 3 

 12s. lid. in addition to the 15s. per day saved in labor; thus 

 showing a clear gain of 4 7s. lid., after paying for the salts. 



