1824.J 



whereby lie lias ascertained, that a com- 

 mon six-peiinj' nail, driven one inch 

 deep, direct info the side of a piece of 

 wood, of different kinds, requires the 

 following; forces, directly applied to tiie 

 heads of the nails, to draw them out, 

 viz. dry hcccli, fi67 lbs. ; dry oak, 607 

 Jl)s. ; s''<'cii sycamore, 312 lbs.; and 

 dry Christiana deal, only 187 lbs. 



Newcastle Crucibles, compounded with 

 powdered Coke, instead of the Blacklead 

 which enters into the composition of 

 German crucibles, have in great num- 

 bers been manufactured by Mr. H. 

 Marshall, liom a mixture of Stourbridge 

 clay, fragments of clay crucibles, and 

 of pit-coal coke ; each vvas powdered 

 in a dry state, and then mixed, and 

 afterwards ground up with water into a 

 jjlastic state. Instead of forming the 

 crucibles on a potter's whirling table, 

 smoothly-turned brass moulds, for the 

 outside and the inside of each sized 

 crucible, arc provided ; and, between 

 these moulds, the prepared clay is 

 pressed with great force by help of a. 

 screw press, by which means, a com- 

 pact and uniform texture is given to 

 these Newcastle crucibles, highly fa- 

 vourable to their enduring heat, and not 

 cracking on being cooled, as is attested 

 Ly a long list of the first-rate metal- 

 lurgists who have adopted them. A 

 great part of the bricks used in London 

 arc made from clay, wherein argil is so 

 much too abundant, and the prepara- 

 tion, or mixing of the same, is so inade- 

 «juately performed, that these bricks 

 would prove quite unserviceable, were it 

 not for the copious mixture of coal- 

 ashes, conlaiuing a great [iroportion of 

 very small bits of cinders or coke, called 

 breeze, with wliicli the clay is mixed in 

 the brick-fields which surround us. 



PaoFEssoR Dcebeuejnek's Experi- 

 ments having created an unusually 

 great interest amongst chemical philoso- 

 phers, it may be proper to state, that, on 

 the 27tli of July last, towards the con- 

 elusion of a course of experiments made 

 at Jena, on the recently discovered pro- 

 perty of the protoxide of platinum, 

 when in contact with alcohol, to cause 

 the latter to attract oxygen from the 

 surrounding air, and to become con- 

 verted into acetic acid and water, it oc- 

 cnrcd to the i)rofessor to try the action 

 of hydrogen gas on the protoxide of 

 platinum ; when 100 grains of the pro- 

 toxide were found to absorb fifteen to 

 twenty cubic inches of the gas, during 

 which ab8or|)tion, so much caloric was 

 evolved, that the protoxide became 



Spirit of Philosophical Disccvery. 257 



ignited, and tlie hydrogen burnt with 

 detonation, as if it had been previously 

 mixed with oxygen or with atraos[ihcric 

 air. Tiie professor next pre])ared some 

 finely divided metallic platinum, by the 

 ligneous decomposition of the ammonia- 

 muriate; (his lie svra])ped np in white 

 blotting paper, and brought it into con- 

 tact with hydrogen gas, but no absorp- 

 tion took place, ncir any other percepti- 

 ble action : but, upon causing atmos- 

 pheri'.; air to have access to the platinum 

 powder in contact with hydrogen gas, 

 after the lajise of a few momenis a 

 remarkable rc-action took place: viz. 

 the compound gas diminished in volume; 

 and, in ten minutes, all the oxygen of 

 the atmospheric air admitted, had con- 

 densed with the hydrogen into water, 

 lie afterwards, on the same day, mixed 

 pure oxygen gas with the bjdrogen 

 gas in contact with the {liatinum pon- 

 der, when a condensation of both imme- 

 diately took place, and the plaliniini 

 became heated to such a degree, that 

 the jiapcr in which it was wrapped was 

 suddenly charred. In thirty repetitions 

 of this experiment immediately made, 

 this rcmajlcable phenomenon uniformly 

 presented itself. 



In every part of Europe these experi- 

 ments appear to have been eagerly re- 

 peated ;iud varied. In Paris, Messrs. 

 Dulong and Thenard discovered, that a 

 spongy state of the platinum is essential 

 to success; in a detonating mixture of 

 hydrogen and oxygen in the i)roportion 

 to form waler, a very thin leaf of plati- 

 num elFcctcd no change when suspended 

 therein for several days; but, when the 

 same leaf was crum|)kd up like the 

 wadding of a gnu, iuid thrown into the 

 mixture, it occasioned its detomtion and 

 instant condensation into water. They 

 also discovered, that palladium and 

 irididium have similar properties with 

 platinum, at common temperatures; 

 and the same with resjiect to cobalt and 

 nickel, but not under 300° Eahrenheit; 

 and with Rhodium, at 464° Fahrenheit. 

 Gold and silver also hare the same pro- 

 perty, b'.it at much higher temperatures. 

 They found the iirescnce of porous 

 i>latinnni, at the common temperature, 

 to occasion carbonic oxide and oxygt.i 

 gases to combine; with a multitude of 

 other interesting results, which our 

 limits will not admit of dilailing. Mr. 

 A. Garden, of London, alter ascertain- 

 ing that si)ongy platinum dues not lose 

 its property of inilaming hydrogen gas at 

 the temperature of freezing, has pro- 

 ceeded to construct several lamps, 

 which, 



