Ifitelligefice and Miscellaneous Articles. 307 



Acids impart stability to the hydruret of sulphurj a little acidulated 

 water is sufficient to produce this effect. In this case it not only 

 does not decompose spontaneously, but the peroxide of manganese 

 ceases to act upon it. — Journal de Pkarmacie, Feb. 18S2. 



ANALYSIS OF MAILLECHORT. 

 An alloy which resembles pretty well silver and polished platina 

 has been manufactured for someyears at Paris : it evidently resem- 

 bles the German silver, now extensively employed in England. M. 

 Dumas (Journ. de Pharm. Feb. 1832,) gives the annexed analysis, 

 which will show that it differs not very materially from that of the 

 German silver, given some time since in the Mechanics' Magazine. 

 MaUlechort. German Silver. 



Copper 66 Copper 53-9 



Zinc 13-6 Zinc 2913 



Nickel 19-3 Nickel 17-^8 



Iron and sulphuret of arsenic. . trace ■ 



Loss 11 10000 



1000 

 Papers on White Copper, which is an alloy similar to the above, 

 will be found in the Phil. Mag. vol. Ixiii. p. 119, and vol. Ixvi. p. 73. 



TRIAL OF CHRONOMETERS AT GREENWICH IN 1831. 



We can advance no better evidence of the advantage of the Go- 

 vernment offering rewards for the improvement of science than the re- 

 sults of the last year's trial of chronometers at the Royal Observatory, 

 and contrasting with tliem the particulars of the trialsin formeryears, 

 showing the gradual improvement and accuracy of performance of 

 the several chronometers that gained the respective prizes. The 

 public are aware that the Lords of the Admiralty give annual pre- 

 miums to the three artists whose chronometers perform with the 

 least variation from mean time, within prescribed limits. In Decem- 

 ber terminated the ninth annual trial of skill of the numerous artists 

 employed in the construction of chronometers. The prizes were 

 awarded to the following makers, whose chronometers at former 

 periods have been repeatedly purchased by the Government. The 

 errors at the close of the trial, as computed by the Astronomer 

 Royal, and determined by what is termed the trial number, were as 

 follows: If 



Mr. Cotterell, Oxford Street 293 ") 



Mr. C. Frodsham, .Tun.,Change Alley. . 3-65 >Trial Number. 



Mr. Webster, Cornhill 3-73 J 



But the actual error on any of their rates during the year did not 

 amount to one second of time; — a degree of accuracy unprecedented 

 in three chronometers in former trials, in which more than five hun- 

 dred have been submittid for observation: so perfectly were they 

 adjusted, that cither \vould liavc enabled a mariner to navigate a 



2 R 2 vessel 



