476 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



great advantage to the Morse instrument now in daily 

 use. 



Another feature of the Little system is the application of 

 an adjustable rheostat; and a third important feature is the 

 introduction of the " lighting blade," which prevents over- 

 winding and breaking of the paper strip. Some forty minor 

 points in connection with his instruments have justified spe- 

 cial patents; among which may be mentioned the punching 

 and perforating machinery, which is a feature common to 

 other instruments, and will probably come into very general 

 use. The Telegrapher, December, 1873. 



PRIZE FOR RAILWAY LAMPS. 



The Society of Arts of London offers a gold medal or 

 twenty guineas for an improved lamp, or means of illumina- 

 tion, suitable for railway passenger carriages, that shall pro- 

 duce a good, clear, steady, durable, and safe light. It must 

 be simple in construction, and capable of being readily 

 cleansed and repaired. In judging the merits, the cost will 

 be considered. Specimens in a condition suitable for trial 

 are to be sent to the society's house not later than the 1st 

 of November, 1874. The council reserve the right of with- 

 holding the medal or premium offered, if, in the opinion of 

 the judges, none of the articles sent in are deserving of re- 

 ward. 23 A, 3Iay 29, 1873, 661. 



STRENGTH OF PERFORATED IRON PLATES. 



According to experiments by Kirkaldy, the diminution of 

 the strength of iron plates by punching and boring for rivet- 

 ing is not entirely accounted for by the loss of the metal re- 

 moved. The breaking weight for a unit of surface of the 

 metal remaining was found to be, on an average, 34 per cent, 

 less for the punched ones, and 23 per cent, less for the bored 

 ones, than for the imperforated plates. 6 C, April 16, 1874, 

 158. 



PRESERVATION OF WOOD. 



In a recent communication to the French Academy, M. 

 Hatzfeld, after presenting a very concise statement of the 

 present condition of practice in this branch of technology, 

 proposes the employment of the tannate of the protoxide of 



