pRoGRFss OF SCIENCE.
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= 1 ce0safS,r CT < .LATlsA iANP.-gy George .1ierY5aee sther, Esq. ef Hkltty-- ID letter to Prefessor Jauseson.--A few years ago, Sir Humphrey Dayy made the discovery. that, fla small platina wire be plac ed around the wick ef a spirit lamp, and rendered red hot, the wire wouldecontinueigniled fora length of time, after the flame was blown out. in consequence ofhaving lately witness ed this singular phenomenon at Pro- lessor iiole's lectures, and that it was generally viewed as nothing more than an amusing experiment., was induced to give ale subject some attention, as felt convinced that mode might be devised of turning il 10 some useful pur- pose.

 On the third of last month, Econtri- ved an apparatus, but not meeting with the success expected with platiua wire, made use of spongy platina, which, found to answer the object had in view. tin order that correct idea may be formed, have made a drawing of this apparatus. The lower part is constructed of tin, in the body of which is the reservoir, large enough to con- tain enart of alcohol; the bottom of the !ntt4 rior of the reservoir is concave, in order that the cotton wick may take np tAe last drop ofthe spirit. After the wick has been spread in the form of eanonet at the top of the lamp, the pla- tina wire cage, containing one piece of spongy platina, is to be picked into the. centre of the wick, and to be kept near iy in contact, but not to-touch 1t. AE ter the reservoir ilas been filled with al- cohol, the wick is to be infamed, and minute afterwards, the sPongy platina will have become ineandescent, when the flame is to be sudednly blown out. and the glass cover 10 be immediately placed over the platina. Without any further care or attention, the platina. will keep ignitcd for thirteen or four

 teen days and nights. A similar apa- ratus has been kept ignited for this pe- riod in the University of this city. If d tube is connected with 6 reservoir icon taining sufficient quantity of alcohol and the bottom of the reservoir of the lamp, l haven Ho hesitation in saving that the platina ball may be keptignited flor years. as the spongy platiha does not appear to hein the least destroyed by being keptin astate of constant ignition.

 1 had similar lamp made, on a small

 scale, to keep ignited from eight to ten. hours, which affords sufficient light to show the face of watch in the dark of night. ltcauses no annoyance from a glare ofiight. If "a light Is required. the glass cover is to De elevated, and the platina gently touched witha match of oxy-muriate of potossa, which viii be instantly inAamed and it is no smalIl recommendation, that there is not the e least dangerto beapprehended fremfirc.

 There have been two objections to this lamp, which were formidable ones,