Analyses of Books. ^ [June. 



and explained, according to their ownldeas, by different philoso- 



j^gf^^nis^oJ l)9J9viT laqqoa lo ed biuoria (|flij:>'I odi "io yDod sHT 



■'." siipf)psiV»g-6;fyg«'n^ drtiJ hfdfbggfig 16 b^ in'fee Wattt5«§ ^ 



Uativeand positive, it is necessary to effect their cotnbinatiori 

 ...it lliei'f.'electritities should be brought into eqttiii'bi'itittf <iif 

 (ffetfeargdd: This' is done by the electrical spark or' flame, whifch 

 6ffers a eonductiiig niediura for this purpose, or by raiaiiig theni 

 €6^ & temperature in which they beconie themselves cohdti'etoi*^ 

 NbW'platiivum, palladium, arid' iridium, are bodies very slightly 

 positive with respect to oxygene ; and though good conductors 

 offelectricity' they ar|e bad conductors and radiators of heat^ and 

 supposing thetii in Exceedingly small masses, they offer to th^ 

 gases the conducting medium necessary for carrying off, and 

 bi-iriging into equilibrium their electricity without any interfering 

 energy, and accumulate the heat produced by this equilibriumi 

 Other metals do not possess the same unibn of qualities; yejl 

 most of them assist combination at lower temperatures tnaa 

 gla^s, which is a non-conductor of electricity." ^ ^-' •^:i;.i nr^od 



■" That spongy platinum, even when moistened,' a§ M-.'DBbfe'^ 

 reiner lias very lately shown, should facilitate the combinatiott 

 6f oxygene and hydrogene, mai/ depend upon this peculiar elec^i 

 trical property; and why foil of platinum should have its poWer 

 of causing oxygene and hydrogene to combine, increased by 

 being placed, for a short time, in nitric acid, as MM. Dulong 

 and The hard have shown, may be owing to this, that the slight 

 positive charge it acquires may, in being brought into equili- 

 orium, be a first step in the operation ; and there are analogous 

 instances." 



'*' Fine wire of platinnm, I find, when conveying currents of 

 electricity; as in a circuit with zinc and sulphuric acid, or char-^ 

 coal and nitro-muriatic acid, has not its power of- acting upon 

 gaseous mixtures sensibly increased." /iiji; j;; i A j j^ /i> - 



^ 'No; 3 relates an explosion of inflammable gas-, which ingeiil^i. 

 Idlikofaly disengaged in coal mines, that took place in llJIS at 

 ihe Salt Works at Aussee, by which several persons were killedii 

 in 66hseefltetite of vfhich the safety lamp has been iritrddtic^din 

 tl^e mines of Styria, Salzburg, and Upper iAustria. The inflartti 

 mcible gas appeared to be derived from bituminous schist* i -4 

 "I'^Wecopy the Articles No. 4 ahd 6 verbatim.siJ'dinoD oi ebam 



"No. 4. I have had some correspondence with MrVBud^l^ 

 j'especting the accidents which have happened in coal mines 

 since the discovery of the safety lamp. He refers them ' iW all 

 cases to the carelessness of workmen, ■''■'i •- - :;•■;>■'.'; Yi.i)^Hj^ 

 ■ '^" I should strongly recommend double^^'ittni^-itt'casfes <»»'litft8 

 miners are obliged to work for any time in explosive mixta?»i 

 6^ wherever currents ' are expected ','-^6t Ifitjips with ■ mica)' or 



tiii-plave witliin the^ire gaiuze to prevent to© gitit a iciricuiatioA 



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