Nov. 17, 1882.] 



KNOW^LEDGE 



399 



M. FAYE ON INTERPLANETARY AIR. 



FEW features in recent scientific developments have a 

 more unwholesome aspect than the reticence with 

 which false doctrines are received by those who know them 

 false — if advanced by men who have (deservedly, perhaps) 

 attained a high position in science. It seems to be re- 

 garded as a point of courtesy to avoid all reference to 

 obvious flaws in reasoning, and to speak only of the pos- 

 sibly correct experiments, well-observed facts, and charming 

 results if the theory were true, leaving altogether out of 

 sight the clear and certain disproof (often multitudinous 

 disproofs) which yet those who thus use flattering words 

 have perfectly recognised from the beginning. I would 

 cite as among the worst illustrations of this weak 

 and unmanly way of dealing with science, the tone in 

 which men who ridiculed among themselves Professor 

 Tait's Sea-bird Theory of Comets' Tails, spoke in 

 public as if it were an admissible and possible theory ; 

 the sUence of those who kneu: about the flaws in Professor 

 Tyndall's Negative Shadow theory of the same phenomena 

 (as if Professor Tyndall, of all men, were such a weakling 

 as to need the unclean sacrifice of untruth, which some seem 

 to love) ; the reticence of many respecting Professor Sir W. 

 Thomson's meteoric theory of the origin of life on the 

 earth ; and the way in which men who are known to have 

 expressed privately their recognition of its fallacy, have 

 publicly written and spoken of Dr. Siemens's theory of 

 solar energy. To my mind, apart from all worthier reasons 

 for objecting to this lip-serving humbug, better suited to 

 Oriental courtiers than to men, it is a very poor compliment 

 to whose whom it is meant to please — it implies that they 

 care more for flattery than for truth, that they are too 

 foolish to see through all this, or fail to perceive the 

 " claw me and I'll claw thee " tone which runs through it 

 all 



We hail then, cheerfully, the sensible and manly, yet (in 

 the best sense) courteous tone in which M. Faye, the 

 eminent French astronomer, has discussed Dr. Siemens's 

 new theory of the sun, giving one among the many com- 

 plete and convincing disproofs of which the theory, being 

 essentially wrong, necessarily admits. M. Faye is not 

 wanting — no man of sense can be — in just appreciation of 

 Dr. Siemens's eminent services to science, but when Dr. 

 Siemens talks paradox, M. Faye does not hesitate (no 

 honest man of science should hesitate) to say plainly that 

 it is so. 



" We know," he says, " that under the action of light, 

 and with the intervention of chlorophyll in plants, the 

 vapour of water and carbonic acid gas are decomposed 

 at ordinary temperatures, and restored to combustible 

 forms, carbon and hydrogen variously associated. Dr. 

 Siemens, an English man of science, has inquired whether 

 the action of the sun alone might not eS"cct this decom- 

 position, when we subject to it the vapour of water and 

 carbonic acid gas greatly rarefied — reduced, for instance, 

 to one 1,800th of atmospheric pressure. These experiments, 

 which only need, in my opinion, a counter-test, easily ap- 

 plied, would seem to have given affirmative results. Thus, 

 gases which had undergone combustion, having been so 

 rarefied that the induction spark would no longer pass 

 through them, a few hours' exposure to solar light sufliced 

 to cause the mixture to let the induction spark pass with 

 the well-known colouring which it takes in hydrocarbonised 

 media. 



" Regarding these five experiments as decisive, Dr. 

 Siemens has been led to ask whether the phenomenon 

 might not play a more important part in the universe than 

 in vegetable life. P^egarding space as filled with analogous 



gases which had already undergone combustion, the Hght 

 of the sun would revivify the combustibles, hydrogen and 

 carbon, which would then be ready to furnish fuel for 

 fresh combustion. 



"In drawing them back to himself and burning them 

 afresh, the sun would recover a large part of the enormous 

 heat, the radiation and loss of which in celestial space we 

 are so pained to see. 



" Dr. Siemens has thus been led to enunciate the fol- 

 lowing hypothesis : — Space is filled with burned gases " 

 (gases the products of combustion, ijaz brdles) — the vapour 

 of water, and carbonic acid gas, mixed with inert gases, 

 nitrogen, &c., somewhat like those of our own atmosphere 

 at l-2000th pressure. These gases would be partially 

 transformed into combustibles under the action of solar 

 light ; then, by a mechanism similar to the air-sucker of a 

 pair of bellows, the sun would draw them back to him, 

 burn them, and send them back into space. This immense 

 source of heat would thus continually revivify itself ; the 

 only part of its radiation lost would be that which would 

 not be absorbed by the cosmic medium l-2000th in density 

 [which, unfortunately for the theory, is nearly all that had 

 troubled us, — the stars being our witnesses. — Ed.]. 



" It is true enough that air at l-2000th pressure would 

 be to the physicist an almost absolute vacuum ; so that, in 

 such a vacuum, the electric spark would not pass. But for 

 the astronomer, such a medium would be quite dense (bien 

 yrossier). When we speak in astronomy of the resistance 

 of a medium on the ather, and with the help of most 

 delicate observations and most profound calculations, se«k 

 the traces of this resistance, ire have something very different 

 in vieiv (il s'agit de tout autre chose). 



"Without entering into details, I note that the trajectory 

 of a cannon-ball, travelling 500'" (547 yards) per second 

 is altered at the end of even only a few seconds, in such 

 sort that astronomers are forced to take into account the 

 resistance of the air in their range-tables. 



"Reducing the air to l-2000th, but raising the velocity 

 of the projectile to that of the celestial motions, 60 times 

 greater, for instance, these coarsely obvious results wouW, 

 for a host of heavenly bodies of dimensions comparable to 

 our cannon-balls (as bolides, flights of shooting-stars, 

 aerolites), be twice as great as in our practice ranges, not 

 at the end of several years or several centuries, but at the 

 end of a few seconds.* 



" Secondly, it appears to me that the eminent English 

 physicist has to some degree omitted to consider the quan- 

 tity of matter he was about to add to the solar system. 

 Under the efl'ect of attraction, this matter would unite 

 itself to pre-existing stars, the sun in particular, and would 

 continually augment their mass. 



M. Faye goes on to consider the mass which would thus 

 be added to the sun, considering only such parts of the 

 interstellar atmosphere as lie within Neptune's distance 

 from the sun. He finds this sphere of interstellar air, even 

 of the tenuity indicated by Dr. Siemens, would amount 

 to about 100,000 times the present mass of the sun — a 

 trifling addition of which astronomers might expect to find 

 some traces in the celestial mechanism. This considera- 

 tion forces us to reject absolutely and decisively an atmo- 

 sphere such as Dr. Siemens and Mr. W. M. Williams have 

 imagined — whatever opinion we form as to the existence 



* Thcio wonid oven, in tho resistiinco of sucli a medinm, 1)0 a, 

 source of additional heat for tlio terrestrial ,i;lobc, quite independent 

 of tlic sun. Judging from certain experiments by Sir William 

 Tlionison on the elevation of temperature of a thermometer moving 

 in air with a certain velocity, that of the terrestrial globo duo to 

 resistance against this raodinm would bo several hundreds of 

 degrees (centigrade). 



