TRANSACTIONS OF THE SECTIONS. 185 



On Improvements in the Defence of Ships of War. 

 By Admiral Sir E. Belchek. 

 The author proposes to construct the ship on the customaiy plan of close iron 

 ribs, but filling up the interstices between the iron with condensed teak. Con- 

 strucling a vessel with 3G inches' depth of rib, at the vulnerable portions to which 

 shot can reach, which vnW probably involve 12 vertical feet of her side, say 8 feet 

 below water and 4 feet above, we should then have a vessel of stronger framework 

 than any now built, building, or contemplated. In lieu of teak the author 

 suggested paper or millboard as very efficacious, having been witness at Algiers, 

 in 1816, to a case in which a ream of foolscap paper, end on, resisted a 68-pound 

 shot. It is of the first importance to provide such a tonnage as shall, in the case 

 of ships of the ' Warrior ' class, be capable of floating the contemplated armament, 

 independent of the forward and after compartments. The first object will be the 

 fortification of the sides, or contour of the oval form of batteiy up to the lines of 

 rolling, by such a disposition of iron framing as may eftectually withstand the 

 hea^dest missile discharged from the heaviest gim afloat with impunity. 



On the New Elevator Gim. By Edwaed Chaeleswoeth. 



On Steam Boilers. By Zeeah Colbtten'. 

 The paper pointed out the causes of failure and bursting, and showed the value 

 of cast iron as a material for the purpose, and that small cast-iron spheres do not 

 retain the solid matter deposited from the water. Small water-tubes and small 

 water-spaces in ordinary boilers always choke with deposit when the feed-water 

 contains lime; but cast-iron boiler spheres, although they may be temporarily 

 coated internally with scale, are found to part with this whenever they <are_ emptied 

 of water. This fact is the most striking discovery that has been made in boiler 

 engineering. It removes the fatal defect of small subdivided water-spaces, which 

 can now be employed with the certainty of their remaining constantly clear of 

 deposit. Cast-iron boilers on this principle, invented by Mr. Harrison of Phila- 

 delphia, are now working in several of the midland and northern counties. Mr. 

 Harrison employs any required number of cast-iron hollow spheres, eight inches in 

 external diameter and three-eighths of an inch thick, communicating with each 

 other through open necks and held togetlier by through tie-bolts. A number of 

 these spheres are arranged in the form of a rectangular slab, which is so set <as to 

 seciire a complete circulation of the water, and several of these slabs, set side by 

 side and connected together, form the boiler ; about two-thirds of the whole number 

 of spheres being filled with water, while the remainder serve as steam-room. The 

 bursting strength of these spheres con-esponds to a pressure of upwards of 1-500 lbs. 

 per square inch, as verified by repeated experiment — between six and seven times 

 greater than that of the ordinary Lancashire boilers of large size. The self-acting 

 scaling action, which has been found to be the same in all cases where the boiler 

 has been worked, has been explained by conjecture. It deserves the careful in- 

 vestigation of the chemist and mechanical philosopher, -with whom the author pre- 

 fers to leave the subject. 



On the Torpedoes used by the Confederate States in the Destrtwtion of some of 

 the Federal Ship>s of War, and the Mode of attaching them to the Hams. 

 By Captain Dott, Confederate States^ Navy. Communicated by Admiral 

 Sir E. Belchee. 



The torpedo consists of a shell filled with explosive material, whether gunpowder 

 or gun-cotton, and is canied under the surface of the water at the end of a bar 

 attached to the stem of the ram or other vessel, projecting some ten or twelve feet. 

 The bar has a slight sliding motion, by means of which the end of the bar within 

 the vessel, as soon as the torpedo strikes the enemy's ship, acts on a simple me- 

 chanical arrangement, bringing the wires connected with the torpedo into circuit 

 ■with a galvanic batterj^, and causing the explosion of the shell. Some small 

 wooden steamers, with such an engine of war attached, attacked the Federal 



