Vol. XXIII. No. i.] 



POPULAR SCIENCE NEWS. 



convection of the earth's heat to it. A little con- 

 sideration will show anv one that ice must form at 

 the surface of a fluid or the hottom, as it is not pos- 

 sible to imagine any arrangement of temperatures 

 that would permit of its formation at an intermedi- 

 ate position. 



Sea-water ice is much less brittle than that of fresh 

 water, rising and falling under the influence of a 

 heavy sea. and adapting itself to the undulations, 

 in cases where the latter would undoubtedly suffer 

 fracture : this is particularly noticeable in the earlier 

 >^tagcs of its formation, in which condition it will 

 not support as much as fresh-water ice, and in giv- 

 ing way, does so without any warning preliminary 

 fissures, leaving a cleanly cut hole of the same di- 

 mensions as the surface over which the rupturing 

 pressure was administered, and thus differs from 

 fresh-water ice, which on fracture carries down a 

 large portion of the surface beyond the area directly 

 under pressure. 



From experiments made on the occasion to which 

 I have referred, it was found that sea-water ice floated 

 with one part above water, and fourteen and eight- 

 tenths below; whilst, expressing tht volume of a 

 given quantity of sea water by unity, its volume, 

 when converted into ice would be 1.0634; and their 

 respective densities as 0.922 to i.ooo. 



The CJuebec Observatory, Oct. 31. iSSS. 



[OrigiiKil in The Hopu'ai- Science yens.] 



i:\PERIMENTAL PROOF OF THE 

 EXISTENCE OF THE ETHER. 



nV I'KOKESSOK \V. M. STrVK. 



I'rof. G. F. Fitzfi;eral(l. in his Presidential 

 address before the section of Mathematical 

 and Physical Sciences at the Hath meeting 

 of the British association, tlisciissed the bear- 

 ing;; of the experiments recently made in Gcr- 

 m<my by Hart/, to prove the material exist- 

 ence of the ether. As the subject is of such 

 vital importance to scientists a short accoimt 

 of the experiment and its influence may not 

 be without interest. 



Ilartz basetl his inve.sti«^ations on the mod- 

 ern conception, well set forth in Clerk Ma.\- 

 well's theories, that electro-magnetic induc- 

 tion must be due to a .stress in an intervening^ 

 mediimi — the hypothetical ether, and that 

 li<(lit and heat plienomena are fo be explained 

 on tlicassiunption that thev are due to electro- 

 maj=;netic distmbancesof a ra])idh alternatinj;; 

 nature ; that the vjuioiis phenomena of elec- 

 tric attraction and repulsion cannot be due to 

 an action at a distance, but on the result of 

 action tiiroufjh a mediinn, since they vary 

 with tile natine of the dielectric ; that a rap- 

 idly alternatinfj ciu'rent woidd produce .s-tre.sses 

 in the supposed ether which woidd be propa- 

 gated as waves with .a definite velocity. v 



Again, the practical luiit of resistance, the 

 British Association ohm, is that resistance 

 which is equal to a velocity of 1.000,000,000 

 centimetres per second. It follows, then, that 

 the resistance of any conductor is equal to the 

 time required for tiie passage of a iniit of 

 electricity through it, and that conductors 

 have tletinite time-constants, as stretched 

 strings iia\c definite periods of vilirations. 

 ,\ secondary circuit will llius jiave tlie maxi- 



mimi inductive etlect produced in it b\- im- 

 pidses whose time-constant of transmissit)n is 

 the same as its ov\n, just as. continuing oiu' 

 analogy of stretciied strings, a string will re- 

 spond best to impidses which cxacth' corre- 

 .spond in time to its own. 



Hart/, produced in the primary circuit im- 

 pulses of an extremely short but definite pe- 

 j riod — one hinidred millionth of a second. 

 I The length and resistance of the circuit was 

 so arranged that this gave a wave length of 

 two metres. Tlie secondary or receixing 

 circuit had a short air-space in it. By the 

 inductive action of tlie primary circuit upon it, 

 sparks were seen to leaj) across this air-space, 

 the sparks being most pronoiuiced when the 

 circuit was at a distance of two metres, or 

 some multiple of it, from a reflector to the 

 primary circuit. This reflector seems to have 

 been simply a wall of the room. Now, as 

 the action of one string upon ant)tiier is not 

 an action at a distance, but through a mediimi 

 — the air, so these residts seem to show that 

 the electro-magnetic action must have taken 

 place through a mediimi. The material ex- 

 istence of the hypothetical mediiun — the 

 ether^is thus rendered pretty certain. 



The a.ssumption of a mcdimn sucii as the 

 ether was a means of co-ordinating the phe- 

 nomena of magnetism, heat and light. These 

 classes of phenomena seemingly so distinct, 

 and in a sense widely separated, \yere imtil 

 late years considered to have very little, or 

 nothing, in common. However, researches 

 in radiant heat and in spectrum analysis 

 showed that heat and light were more closely 

 related, and must both be due to di.sturbances 

 transmitted by a medium. A little later on, 

 the close relation in the transmission of light, 

 heat, and electro-magnetic di.stiubances was 

 demonstrated, and Clerk Maxwell developed 

 his theory of light, that it was due to the ac- 

 tion of stresses of a rapidly alternating char- 

 acter in the ether, and that these were similar 

 to the .stresses due to electro-magnetic action. 

 As a proof of the correctness of his theory, 

 he showed that tlic velocity of electro-mag- 

 netic impulses in a non-conductor was about 

 equal to tiie yelocit\- of light. The results of 

 Hart/."s experiment seem to prdxe the correct- 

 ness of his theory in a striking manner. 



The admirable train of reasoning which 

 led Maxwell to this theory by clear methods 

 of induction, are comparable f>nly to that mas- 

 terpiece of inductive reasoning on the part 

 of Adams, which, in 1846, led to tlie disco\- 

 eyy of the planet Neptune. 



The electro-magnetic theory of light satis- 

 factorily explains why the waves of light and 

 heat have transverse rather than longitudinal 

 vibrations. 



It remains for careful investigation to ac- 

 cmately ascertain tiie natmx and property- of 

 the other, and to reconcile some contradictory 

 conceptions which demand that it ha\c s\icli 



high rigidity and elasticity, when its density 

 is almost imthinkablv small when compared 

 with water. 



.Scientists may now congratidate themselves 

 upon their cotu'age in adhering to the concep- 

 tion of an all-per\ ading medium, such as the 

 ether, in spite of the jeers of certain meta- 

 physicians, because they were ignorant of its 

 possible structure and many of its laws. 



From the results of this and similar experi- 

 ments we may look for a great change in text- 

 books on the subject of attraction. They 

 will treat the attraction of gravity and attrac- 

 tion in general, as due to stress in the ether 

 and not to action at a distance. The immense 

 gain in clearness to the beginner will be ap- 

 preciated by those who remember how they, 

 struggled over these knotty points in the out- 

 set of their scientific .studies. Then, too, the 

 various, and to some extent often inexplicable, 

 manifestations of chemical affinity mav be 

 explained and co-ordinated by being proven 

 to be a form of ether-stress. 



We may confidently look to inventive genius 

 to discover some means of utilizing the energy 

 of the diflerent forms of ether-stresses, and 

 the ether-engine may not after all be a dream. 

 The subject is at least fascinating and prom- 

 ising and may give us a key to the .solution of 

 that important scientific and commercia 

 problem — ho\y to utilize the solar energy di- 

 rectly as a motive power. 



Atiikxs, Ohio. 



TIIK IXTERN.\TIONAL GEOLOGICAL COX- 

 GltES.S. 



HV K. H. CI.AVI'OI.E. 



Amoxo all the sciences Geology has found the 

 struggle for existence the hardest. Encumbered 

 from its birth with theories connecting physical 

 phenomena with the government of moral beings, 

 its growth has been a violent and long continued 

 contention with doctrines supposed to be of vital 

 importance to mankind. The penal nature of the 

 visitations of fire and water, whose terrors linger in 

 the legends of almost every race, and whose effects 

 may be plainly read in almost every land, weighed 

 down the f'gyptian philoso|ihers in their inquiries 

 into the causes of such dire catastrophes. -The 

 sages of Greece and Rome could scarcely free them- 

 selves from the paralyzing effects of the .same tenets, 

 and surviving the vicissitudes of war it arose in the 

 tenth century of our era to thwart and silence the 

 investigations of the Saracens. 



.\mong Christian nations, the Italians were the 

 first to revive the study of the surface of the earth. 

 In the earlier part of the sixteenth century the ma- 

 rine shells and other organic fossils found abundant- 

 ly in the strata of Italy attracted the attention of 

 scholars and led to an animated controversy on the 

 nature and origin of the phenomena. Sound rea- 

 soning founded on observations, was not wanting 

 in this discussion, but absurd and fantastical theo- 

 ries prevailed, and, as they were maintained with 

 much skill and suited the popular taste, more than 

 a century passed before it was admitted that the so- 

 called petrifactions could ever have formed parts of 

 living organisms. .\t this point theologians en- 

 tered the field in Italy, Germany, France and Eng- 

 land, and nearly two himdred years more were con- 

 sumed in efforts to reconcile all data with the cos- 



