70 ANNUAL OF SCIENTIFIC DISCOVERY. 



"The three jioints of the patent are, — 1st, Retention of the un- 

 coiisimii'd jrases, 2fl, Reverljonitiou by a eircuhir chamber of 

 l)roper rekitive heij2:ht in the two curves. 3il, A tlue s,upply of 

 heated air in the clianiber, and between its phites, doinj^ away 

 with (b-aft in front and from below, after the lire is once kindled, 

 afVordin;; safety from lire by closed furnaei! doors, freedom from 

 water which would put out the fires (l^y closed ash-pit), and i)re- 

 per\ation of iron in locomotives by the constant current of the 

 burniiii^ jjases in the chaml)er." 



It is claimed that, by tiiis furnace, a savini; of twenty to forty 

 per cent, in fuel is cll'ected, and that with fuel even of the poorest 

 quality. 



ON IRON SHIPS. 



"Mr. "William Fairbairn communicates to the " Quarterly Journal 

 of Science," for April, bS(!(i, a paper on the loss of the "Londtm" 

 Steamsliip, Miiich foundered at sea on a voyage to Australia, from 

 which thi" foUowint^ an- extracts : 



"The introduction of iron for the purposes of ship-building has 

 given greatly increased strength, and allbrded facilities for obtain- 

 iu<X new forms, which, aided by the power of steam, have insured 

 a rate of speed in vessels never before attained in naval histoiy. 

 It has, moreover, furnished the naval ai'chitect with a material of 

 immense value as regards construction ; and its careful distribu- 

 tion in the shajie of x'il)S, frames, and the sheathing of vessels, 

 cannot be too higldy api)reciated. As compared Avith the best 

 English oak, it exhibits four times its power of resistance ; and it 

 lias, in addition, the double advantage of being almost perfectly 

 homogeneous and free from the defects of open joints, which, in 

 tlie ciise of the planking of wooden vessels, require to be caulked. 

 AN'itii all these advantages, iron constructions are surrounded with 

 many dangers, when entrusted to the care and superintendence of 

 incompetent persons. In such hands there invariably exists a 

 want of pnjportion in the formation of iron vessels, which exhil^it 

 defective jiowers of resistance, and such other abnormal condi- 

 tions as might prove destructive to the efficiency and ultimate 

 security of the structure. It is of importance to take into account 

 the forms or lines of least resistance, such as a fine entrance at the 

 bows, and an equally clear run at the stern, if high sjieed is to be 

 obtained. The forms advantageous for vessels navigating rivers 

 and smooth water are not so in those intended for long sea- 

 voyages, and having to contend with the waves of the Atlantic. It 

 is "questionable, in the latter, whether or not some slight sacrifices 

 should be made to speed, and some modification eflected in the form 

 of the bows and stern, in order to meet all the requirements of a 

 safe and convenient vessel intended for the double purpose of 

 carrying passengers and cargo. The safety and success of a ves- 

 sel do not depend so much on its speed as upon its sea-going 

 properties and sound construction. If, for example, we take one 

 of the present iron clippers, with her sharp bows and fine propor- 

 tions, I am of opinion that she is neither the safest nor the best 

 description of vessel to contend with a heavy sea in foul weather. 



