Chemical Science. 173 



4. Odoriferous Lamp. — The peculiar property which Dobereiner 

 discovered in spongy platina, of causing the union of hydrogen and 

 oxygen with extreme facility, and at temperatures much below those 

 ordinarily required for the purpose, led him to examine into the 

 chemical changes analogous to combustion, which other bodies 

 could undergo by the same or similar means, and he soon found 

 that alcohol vapour in the open air, and under the influence of the 

 prepared platina, became converted into acetic acid. The experi- 

 ment then became nearly the same as that founded upon Sir H. 

 Davy's discovery of the power of a heated platina wire, in continu- 

 ing the combination of combustible bodies and supporters of com- 

 bustion without flame ; and it ultimately gave rise to the formation 

 of a lamp, which, containing alcohol, and prepared at the place of 

 the wick with a piece of spongy platina, or, as Dobereiner calls it, 

 sub-oxide of platina, or some other form of that metal, gradually 

 converted the whole of the alcohol into acetic acid. 



The lamp in this form has been used for a night-lamp ; it gives 

 light enough to see the time by a watch held close to it, and if more 

 light be required, a piece of amadou may be carefully inflamed at 

 it, and then a light procured in the usual way. M. Batka has pro- 

 posed to use Eau de Cologne in place of common spirit of wine, 

 and finds, that then the fragrance diffused is very grateful, being, in 

 fact, occasioned by the actual formation of aromatic vinegar during 

 the whole time the lamp burns. We doubt, however, whether a 

 constant odour of this kind is desirable, unless indeed there be some 

 bad smell to cover, and think that much more pleasure is derived 

 from the inhalation of a perfectly pure and sweet atmosphere with 

 the short occasional presence of fragrant odours, than from an at- 

 mosphere constantly, or for any long time aromatized. 



5. Electricity of the Solar Rays. — (Letter from Sig. Carlo Mat- 

 trucci of Forli, to Professor Gazzeri.) " I hasten, Sir, to communicate 

 to you some experiments which appear to me to deserve the attention 

 of philosophers. Having been for a long time persuaded of the 

 existence of electricity in the solar rays, I wished to ascertain the 

 fact by experiment. Having for this purpose exposed to the sun 

 a delicate condensing electrometer of gold leaf, I soon perceived 

 the leaves diverge and open themselves also on that side of the 

 glass case which was directly exposed to the solar action, as if they 

 had been attracted by it. Being induced from this first fact to 

 suspect glass in this situation electrified, I was anxious to know if 

 this were the case : wherefore, having left some plates of it in the 

 sun, in a few moments I touched them in different places with the 

 ball of the electrometer, when a very perceptible divergence ensued, 

 which, however, was much more apparent when I touched the 

 plates, although lightly, with a flat surface, since the effects of the 

 friction and the pressure did not afford a doubtful result. I con- 



