SCIENTIFIC SUMMARY. 
321 
is to be deliberately weakened near tbe bottom of each inner cell. When a 
torpedo explodes against tbe outer skin, it is expected that the shock will 
break through the middle skin at its weak points. Then the outer skin will 
be driven in, forcing the water into the cells between the middle and inner 
skins against the cushion of air contained in them. The work so expended 
will, it is hoped, save the inner skin from injury, except with very powerful 
torpedoes. After the explosion the inner cells may be cleared of water by 
attaching hose to the union joints and forcing in air. Nothing but actual 
experiment can decide on the value of such a plan, but it is believed to be 
the first suggestion yet made for providing structural means of resisting 
torpedo attack. 
New Technical Journal. — Mr. E. J. Reed, C.B., the late Chief Constructor 
of the Navy, has started a new quarterly magazine dealing with subjects 
relating to naval architecture and marine engineering, which bids fair to 
render very great service, not only to those professionally engaged in the 
construction of ships and engines, but to the much larger circle of readers 
requiring information on such subjects of a reliable character. The articles 
in the first number of the new magazine are many of them by writers of 
eminent experience and knowledge, and range over a field including both 
special technical subjects, and others of more general interest. The articles 
on the stability of ironclads, the structure of iron ships, and the stowage of 
merchant ships, are of the former character. Those on the proposed Naval 
University, on naval tactics, and on the necessity of forming a naval staff, 
with the very severe review of the criticisms on the navy contained in Mr. 
Hawksley’s presidental address, at the Institute of Civil Engineers, will be 
of interest to a very wide circle of readers. 
H.M.S. Thunderer. — This powerful ironclad, a sister vessel to the 
Devastation , has recently been launched at Chatham. She is one of the 
mastless ironclads designed by Mr. Reed in 1869. The armour generally is 
12 in. thick, but 14 in. in the neighbourhood of the port-holes. On the 
sides of the breastwork, in parts where a shot penetrating would do no 
harm to the machinery of the turrets, the armour is reduced to 10 ins., and 
it is also reduced to 10 ins. in the lower strake on the sides of the hull. 
The vessel has a sharp spur for ramming, and is short and handy. She is 
driven by engines guaranteed to give 5,600 indicated horses power, and will 
be armed with four 35-ton guns. 
Wind Pressure on Inclined Planes. — Mr. Wenham and Mr. Browning 
have carried out some new experiments with a very delicate instrument on 
the pressure of a current of air on inclined planes. The results have been 
communicated to the iEronautical Society, and will be of interest not only 
to those who are studying the mechanism of flight, but also to engineers 
who have often to calculate the effect of wind pressure on their structures. 
The Westinghouse Air-break. — This is a form of continuous break, or 
break applicable simultaneously to all the carriages of a railway train, which 
has been in use for about three years in America, and is now being tried in 
this country. An air-compressing pump is fixed on the locomotive engine, 
delivering the air into a reservoir under the foot-plate. The speed of the 
pump is. self-adjusting, the valves being so set that it just keeps moving 
against the full pressure in the reservoir, and when the pressure in the 
YOL. XI. — NO. XLIY. Y 
