•ICIEKTIFIC WfiWS. TT 



Utter from Profcjfor Vrovst io J. C Delamctherie on a dan- 

 gerous fulminating Powder'^, 



IN one of my late leaures, I made an experiment thai Dangerous ex^ 

 might have been attended with ferious confequences to fome P"'"^^*^'- 

 of my auditors. 



It is, perhaps, no exaggeration to fay, that the mixture of ^ 



oxigenated muriate with arfenic, takes fire with the rapidity 

 of lightning. 



I am accuftomed to compare the quicknefs with which Mode of com- 

 difFerent kinds of powder burn, by fetting fire to them in wkh^thaf of ^"* 

 cannons of equal diameter, paffing each through a piece of gun powder. 

 cork placed in water, fo as to fink in it almoft their whole 

 length. 



In this manner I was defirous of burning the arfenical mix- A mixture of 

 ture, by the fide of an equal quantity of gun- powder, in ^j^^^ ^^^ arfenic 

 order to compare their flame and continuance ; but I had burnt with the 

 fcarcely time to draw back a little after fetting fire to the two '^f^g^'^bSrftlhe* 

 cannons, when the firft exploded and burfi:, breaking the cannon that con- 

 glafs velTel, and throwing about the water in all the radii of ^^j'^^^'^''^^"^"- 



*' '^ ed It quite flat, 



the furrounding fphere. Though the mouth of the tube and andthrewabout 

 the efcape of the flame were perfe6lly free, the cannon was ^^e water in 

 burft from top to bottom, and fpread out as flat as a card. ]„ alldireaions. 



This powder is fo violent in its eflfeds, that I conceive it Its effefts are toa 

 would be very dangerous, to attempt to make any ufe of it. ^j"^^'°"^ ^^ 



If two long trains be made on a table, one of gun-powder A long train of 



the other of this mixture, and they be in contad with each 'F.^'^f.^^P^^''.^ 



liK.6 liftntnin*'. 

 •ther at one end, fo as to be fired at the fame time, you will 



^yfee with great furprize, that one difappears like a flafti of light- 



IfJiing, while the other feems to burn with extreme flownefs. 



tetter from a Correfpondent on the Expediency of converting 

 I'oreii^n Weights and Meafures into Englijk. 



To Mr. NICHOLSON. 

 SIR, 

 THE pleafure which your readers receive from the perufal 

 of your Journal is fo much abated by the obfcunty arifing 

 from the names of the French weights and meafures, that I 



Journal de Phyfiqae, May, 1803- p. 394. 



with 



fc 



