1865.] Physics. 697 



vapour over red-hot charcoal dust. The mixture of carbonic acid, 

 carbonic oxide, and hydrogen produced is then passed through milk 

 of lime, to remove the first, and the other two go on to be mixed with 

 air, and exploded in the cylinder of the engine. Extending the use of 

 the engine as mentioned above, M. Arbos's apparatus effects a great 

 saving in the cost of working the machine. Gas produced for two 

 francs will do the work of six or eight francs' worth of coal gas. 



A new combustible has been invented by a gentleman appropriately 

 named Stoker, which is likely to possess some useful properties. It 

 appears to be very pure charcoal, finely ground and made into a paste 

 with starch. The paste is moulded into cakes or balls of different 

 sizes, and then dried. When perfectly dry these may be lighted with 

 a lucifer match, and will continue to burn steadily, like German 

 tinder, without giving flame or smoke, The combustible is intended 

 for heating urns, chaufferettes, &c. 



Electricity. — In our last " Chronicles " we gave a brief account 

 of a theory of imponderables, laid before the Academy of Sciences by 

 M. G. Martin. In reference to this subject, two communications 

 have reached us from gentlemen who consider the theories there put 

 forward as sufficiently valuable to be worth claiming, on the ground 

 of previous publication. The first is from Mr. McGauley, who it 

 seems sent a memoir, in which this theory was developed, to the 

 Academy, in May, 1862. It was then referred to a commission, 

 consisting of MM. Pouillet and Fizeau, who have never reported 

 upon it. In an article in the ' Scientific Eeview ' the author states that 

 " three years have confirmed the conviction his researches had long 

 led him to entertain, that the imponderables are really material 

 elements, subject, like all others, to definite laws of combination." 

 We extract the propositions laid down by the author at the commence- 

 ment of his memoir : — 



" Motion, Electricity, Heat, and Light, consist of the same Constituents, 

 either Singly or in Combination. 



" 1. The simplest form of motion (including nervous energy), 

 electricity, heat, and light, is an element of motion in the latent 

 state — that is, combined with matter. 



" II. When an element of motion is liberated from combination 

 with matter, by the neutralizing action of a motive element of the 

 opposite kind — that is, ' when two opposite motions destroy each 

 other,' the two electricities are set free, and when these combine, Heat 

 is the result. 



" III. When one of the calorific elements is in excess (being com- 

 bined as a motive-element), the resulting heat becomes either one of 

 the coloured rays of the solar spectrum, or an actinic ray, according 

 to the amount of such excess, and is the more refrangible in propor- 

 tion to that amount. And it is probable that the nature of the light 

 which results depends on which calorific element (electric element) is 

 in excess. 



