On the Freservation of Provisions and Gooas. 141 



When the vapour of spirits of turpentine is made to issue from 

 a small orifice, and inflamed, it burns, and throws off large quan- 

 tities of smoke ; but when a jet of steam is made to unite with 

 the vapour, the smoke entirely disappears. When vapour of spi- 

 rits of turpentine and of water are made to issue together from 

 the same orifice, and inflamed, no smoke appears. Hence its 

 disappearing, in the above experiment, cannot be supposed to 

 depend on a current of atmospheric air. 



When a jet of steam is thrown into the flame of aspirit-of-wine 

 lamp, or into flames which evolve no smoke or carbonaceous 

 matter, the same effect is produced as by a current of air. 



It appears from these experiments, that in all flames which 

 evolve smoke, steam produces an increased brightness, and a 

 more perfect combustion. 



Now, with a very simple apparatus, steam might be intro- 

 duced into the flames of street-lamps, and that kind of lamp 

 which is used in butchers' shops in London, and in all flames 

 which evolve much smoke. The advantage of such an arrange- 

 ment would be a more perfect combustion, and a greater quantity 

 of light from the same materials. The flame of the lamps, to' 

 which steam is applied, might be made to keep the water boil- 

 ing which supplies the steam. 



I hope the above mav not be altogether uninteresting and use- 

 less to the readers of your journal. 



Very respectfully, your obedient servant, 



J.F.Dana. 



XXIV. On the Preservation of Provisions and Goods. By 

 Joseph MacSweeny, M.D. 



To Mr. Tilloch. 



^j^ London, Aug. 17, 1819. 



Sir, — 1 HE facility with which cutlery of every kind may be 

 put in water deprived of oxygen by iron-filings, and covered with 

 oil, makes it a matter of some consequence to ascertain whether 

 a large (piantity of iron has the power of decomposing water at 

 ordinary temperatures. Unbiassed by any opinion on the subject, 

 and desirous only of arriving at truth, I have been led to make 

 the following experiments. 



I put a quarter of an ounce of iron-filings in two ounces and 

 a half of water boiled and covered with oil ; at the end of twelve 

 days the ajjpearance of the iron- filings was unchanged. I put 

 a large quantity of iron-filings in a phial, and covered them with 

 a layer of warm water about a quarter of an inch thick, the water 

 was covered with oil, a bent tube was attached to tiie phial, and 

 the end was left under a receiver in a pneumatic apparatus durmg 



a week: 



