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POPULAR SCIENCE REVIEW. 
the designer of most of the American Monitors, after defending the Monitor 
system, states his conviction that impregnability is no longer attainable by 
the application of a belt of armour reaching a few feet below the water-line. 
“Up to the present time,” he says, “Mr. Reed (the Chief Constructor of 
the English Navy) has unquestionably distanced all his competitors j the 
‘ Thunderer ’ and ‘ Devastation ’ are in fact impregnable above water. But 
it will soon be found that invulnerability calls for devices wholly different 
from those which are now deemed sufficient. Much has, however, been 
gained by the British Admiralty carrying out Mr. Reed’s adaptation of the 
Monitor system. The problem has thereby been greatly simplified, and all 
further speculation as to what ought to be done above water may now be 
regarded as waste of time. The field has been most materially reduced ; 
our labours being now confined to devising means for piercing the hull below 
the point that terminates the protection for which Mr. Reed is indebted to 
the skill of Sir John Brown.” 
Longitudinal Framing of Ships. — Mr. E. J. Reed, the Chief Constructor of 
the Navy, has recently called attention to the loss sustained by merchants 
from the persistence of shipbuilders in adhering to the transverse system of 
framing in ships. On the longitudinal system, introduced originally by Mr. 
Scott Russell, and adopted with modifications by the Admiralty, a given 
strength can be obtained with considerably less weight of hull. 
Armour-plate Fastenings. — In combination with the system of raised screw 
threads for armour-plate bolts, Major Palliser and Lieut. English have intro- 
duced a form of nut with spherical bearing surfaces. The spherical nut fits 
in a spherical recess formed in the armour-plate, or on a washer with a 
spherical seat. These bolts and nuts can adjust themselves to the twisting 
of the plate produced by the impact of shot, and are less liable to be wrenched 
off. In conjunction with a plan of backing armour-plates for land defences 
with “ iron concrete,” they are being tried at Shoeburyness. 
Whitworth and Palliser Shot. — Major Palliser has challenged Mr. Whit- 
worth to a competitive trial of the relative penetrative power of chilled, 
pointed, and steel flat-fronted shot. 
Atlantic Railway . — In his recent presidential address to the Institute of 
Civil Engineers, Mr. Vignoles, C.E., F.R.S., alluded to the Atlantic Railway 
and the Suez Canal. In regard to the former, he stated that he had received 
authentic intelligence that on the day previous to the formal opening of the 
line, ten miles were laid by one working party and eight miles by another. 
An official inspection, since the opening, has been made, and the conclusion 
has been arrived at that it will require a further expenditure of some two 
millions sterling to perfect the way and to comply with the conditions of 
the contract. These requirements have not been thought unreasonable, and 
the money is forthcoming for their execution. Meanwhile, the traffic 
throughout is continued without interruption. — In regard to the Suez Canal, 
he stated that between May 15 and June 15 of last year, 58 steam dredgers 
and 11,000 labourers were at work, and upwards of 2£ millions of cubic 
yards of material were excavated, being at the late of 80,000 cubic yards 
daily. lie expected that in the coming spring a depth of 20 feet of water 
throughout will be attained. He believed that it would prove a very ex- 
cellent financial speculation. 
