522 SCIENTIFIC RECORD FOR 1882. 



Use of Quicklime in Blasting. 



An interestiug application of the force resulting from the expansion 

 due to hydration is recorded in Nature. To obviate the danger at- 

 tending the use of explosive substances in coal mines, the following 

 process has been successfully employed in Derbyshire; A series of 

 holes six feet apart and about three feet in depth are drilled into the 

 coal at the proper points; these holes are then filled with cylinders of 

 compressed quicklime, each 2^ inches in diameter and 4^ inches long; 

 each hole receives seven of these blocks. A groove in each cylinder 

 admits the insertion of a ^-inch pipe which extends a few inches beyond 

 the aperture of the drilled hole; through this pipe water is forced by a 

 small hand pump. Each hole is of course firmly tamped with paper 

 and rubbish. Soon after the water is introduced a sound as of escap- 

 ing steam is heard, here and there the tamping is blown out, and in a 

 few minutes the whole mass of coal is throw^n out from the face upon 

 "sprags," short timber props placed to receive it. The time required 

 in the various operations is as follows : drilling 12 minutes, charging 

 4 minutes, watering 2 minutes, total 17 minutes for each bore hole. 

 {Nature, xxvi, p. 298.) 



ORGANIC CHEMISTRY. 



Formaldehyde (or oxymethylene) has acquired great importance within 

 a short period, the researches of Baeyer, Wurtz, and others having 

 shown that it forms an intermediate product between carbonic acid 

 and carbo-hydrates in the physiology of plant-life. It may be regarded 

 as the first product of the assimilation of carbonic acid by plants, and 

 by simple polymerization and elimination of water, is probably capable 

 of producing sugar, glucose, starch, and cellulose. 



B. Tollens has described a convenient method for preparing this sub- 

 stance, which is based upon the oxidation of methylalcohol by air and 

 incandescent platinum. For details we refer to the original paper. 

 {Berichte d. cliem. Oes., xv, p. 1629.) 



Curciimin and other Substances from Turmeric. — C. Loring Jackson 

 and A. E. Menke give the following : Bengal turmeric root is ground and 

 treated in an extracter with ligroine to remove turmeric oil, and then 

 the curcumin, mixed with a large quantity of resin, is extracted with 

 ether and finally purified by crystallization from alcohol. The average 

 yield of curcumin was 0.3 of one per cent. The mean of five analyses 

 indicates the following composition: 



Carbou 08. 30 



Hydrogen 5. 03 



Curcumiu crystallizes from alcohol in stout needles often in radiating 

 groups. It has an orange to yellow color with p. blue reflex; its ether 

 solution fluoresces green ; it melts at 17S0 C. It is nearly insoluble in 

 water, slightly in benzol, readily soluble in hot alcohol, and more read- 



