Magnetic Polarity of Rifles. — Mr. Spiller one of tlie Chemists in 

 the Royal Arsenal, Woolwich, has observed that all the rifle barrels used 

 by the Arsenal Volunteers exhibit, after repeated firing, decided magnetic 

 properties ; the region of the breech being possessed of north polarity. 

 This appears to be due to the repeated concussions caused by the explosion 

 of the powder, whilst the rifles are held in the direction of the range, Avhich 

 runs nearly parallel to the magnetic meridian. 



A Flash of Lightxing. — A Sniatterer writes : — A stout iron hook 

 part of a set of block pulleys, snapped while an iron casting weighing near 

 four tons was being lifted. The iron was found defective in texture and 

 in forging. At the moment of breaking, a bright flash of light was distinctly 

 seen between the broken fragments. Is this a usual phenomenon ? If so, 

 what is its natiu-e, or how accoimted for ? This occurred in broad day- 

 light, with fine drizzling rain falling at the time ; and the flash was 

 described as from eighteen inches to two feet long. 



Geology.— The following are the dimensions of the skeleton of a 

 Mastodon just discovered 50 feet below the surface of a peat-bed near 

 Troy. Tusks, 6 feet long, and 9 inches in diameter. Ribs about 4 feet 

 long, the largest 4 feet 9 inches. Upper jawbone 4 feet 9 inches long, 

 and 3 feet across the forehead. The sockets of the eyes are described 

 as nearly large enough to admit a man's head. H ip-bone 5 feet long ; 

 shoulder-blades 2 feet 9 inches. Diameter of leg-bone at the knee-joint 

 13 inches. The vertebrse 18 inches diameter. 



It is ascertained that nearly all the Chinese coalfield belongs to the 

 Mesozoic period, no carboniferious fossils being present, but their place 

 being supplied by cycadeous plants. 



Botany — Skeleton Leaves. — " The following method has been com- 

 municated to the Botanical Society of Edinburgh : — A solution of 

 caustic soda is made by dissolving 3 oz. of washing-soda in 2 pints of 

 boiling water, and adding 1^ oz. of quicklime, previously slaked; boil for 

 10 minutes, decant the clear solution, and bring it to the boil. During 

 ebullition add the leaves; boil briskly for some time — say an hour — occa- 

 sionaly adding hot water to supply the place of that lost by evaporation. 

 Take out a leaf and put it into a vessel of water ; rub it between the fingers 

 ixnder the water, if the epidermis and parenchyma separate easily, the rest 

 of the leaves may be removed from the solution, and treated in the same 

 ■way; but if not, then the boiling must be continued for some time longer. 

 To bleach the skeleton, mix about a drachm of chloride of lime, with a 

 pint of water, adding suflicient acetic acid to liberate the chlorhie, steep the 

 leaves in this till they are whitened (about 10 minutes), taking care not to 

 let them stay in too long ; otherwise they are apt to become brittle. Put 

 them into clean Avater, and float them out on pieces of paper. Lastly, 

 remove them from the paper before they are qiiite dry, and place them in 

 a book or botanical press. Dr. G. Dickson." Hardwick's Science 

 Gossip. 



J. N. 



