MECHANICS AND USEFUL ARTS. 47 



nently under water, is the Kingston limestone, furnished by 

 Noon and Madden. These stones have both beds cut, but the 

 sides and builds loft rough, with vertical quarry joints, the projec- 

 tions not exceeding 2 inches. The beds are exceptionally wide. 

 As the base of the masonry work resting on the timber is very 

 much larger than the section of masonry at the water level, it is 

 considered that this class of masonry is equally as good, and cer- 

 tainly far cheaper than regular dimension stone. All the stone 

 in any one course are cut to a uniform size. Above low water 

 granite will be used on the water face, and subsequently through- 

 out as freestone. 



The first or corner-stone of the extensive pile of masonry to be 

 raised above the caisson, unlike as it was to ordinary affairs of 

 this kind, was a massive block of limestone from the quarry at 

 Kingston, Ulster Co., and in extent was 3 feet wide by 8 in 

 length, weighing about 5,800 pounds, or 165 pounds to the 

 cubic foot; and it is of this material that the foundation below 

 low-water mark will consist. 



Additional borings are now being made for the New York tow6r. 

 The boring made 2 years since was 400 feet away from the act- 

 ual site of the tower. This one is directly on it. The same 

 stratum of 30 feet of the finest quicksand has been penetrated, 

 but boulders have been encountered at a depth of 80 feet, and the 

 indications are that rock will shortly be reached. 



CONCRETE AND IRON BRIDGE. 



A new bridge erected for Sir Shafto Adair, from the designs of 



O 



Mr. H. M. Eyton, of Ipswich, over the TVaveney, at Homers- 

 field, England, has been recently tested. In designing the bridge 

 advantage was taken of the principle of Messrs. Phillips' patent 

 fire-proof construction, -- a system in which all the iron-work is 

 completely embedded in Portland cement concrete. The bridge 

 has one arch of a clear span of 50 feet, with a rise of 5 feet 3 

 inches. The skeleton of the bridge is of iron, and this is en- 

 tirely filled in with Portland cement concrete, and rendered with 

 Portland cement, thus forming one continuous beam, getting 

 stronger every year, in addition to the iron skeleton, which is of 

 itself sufficient to do the ordinary statical work of the bridge ; 

 the weight of concrete alone is over 100 tons. The spandrels of 

 the bridge are relieved by a raised panel, and in the centre is a 

 casting of the Adair arms, taken from the old 3-arched brick 

 bridge. The first test applied was that of a 5-ton road roller 

 'drawn by 4 horses. This was passed across several times, and 

 not the least deflection was perceptible. Afterwards a heavy 

 wagon, laden with sacks of flour, weighing altogether 6 tons, 

 was passed over, and still, it is stated, no deflection could be 

 noticed. 



BRIDGE OVER THE DNIEPER. 



The railway bridge lately erected over the Dnieper, near 



