Miscellaneous Intelligence. 



i. This portion was pulverised still further on an agate plate, 

 with an agate muller, for twenty minutes. Being then col- 

 lected, it was found more bulky in volume than before, and 

 increased in weight 120 grains ; the whole quantity now being 696 

 grains. 



ii. 288 grains of this were pulverized anew, in the same manner 

 and for the same time : the volume increased a little ; the weight 

 increased from 288 to 342 grains. 



iii. Two gros (118 grains) of the latter portion, pulverized again 

 for the same time, increased in weight 31 grains. 



iv. A third rubbing on the agate for nine minutes, caused an 

 increase in weight of 6 grains. 



V. A fourth rubbing for fourteen minutes increased the weight 

 10 grains, so that by successive pulverization, the two gros had 

 increased in weight 47 grains. 



vi. Another rubbing was given to the powder, but the matter 

 seemed incapable of further division under the muller, and the 

 increase was only 2 grains. 



For the purpose of ascertaining to what the increase of weight 

 was due, half an ounce of that mentioned in the second experiment 

 was heated and stirred in a porcelain basin ; being then weighed, 

 whilst warm, the excess of 54 grains was found diminished to 43 

 grains. The weight of the plate and muller were not sensibly 

 changed in these experiments, and the surface was scarcely altered. 

 -^Recueil Industriely vii. 64. 



8. Friction of Screws and Screw-presses. — An examination of the 

 friction in screws having their threads of various forms, has led M. 

 Poncelet to this very important conclusion, namely, that the friction 

 in screws with square threads is to that of equal screws with trian- 

 gular threads, as 2.90 to 4.78, proving a very important advantage 

 of the former over the latter, relative to the loss of power incurred 

 in both by friction. 



9. Paper Linen. — According to the Paris papers a new invention, 

 called papier Huge, has lately attracted much attention. It consists 

 of a paper made closely to resemble damask and other linen, not only 

 to the eye but even to the touch. The articles are used for every 

 purpose to which linen is applicable, except those requiring 

 much strength and durability. The price is low, a napkin costs 

 only five or six centimes (about a halfpenny), and when dirty, they 

 are taken back at half price. A good sized table-cloth sells for a 

 franc, and a roll of paper with one or two colours for papering 

 rooms or for bed curtains, may be had for the same price. — New 

 M. Mag. xxiv. 545. 



10. Hardening of Steel. — According to M. Altmutter, when steel 

 is hardened by being quenched in any other liquid than mercury, it is 



