SCIENTIFIC SIDE-LIGHTS 



476 



while the scheme of the universe may be in- 

 finite, both in time and space, it is presump- 

 tuous to suppose that all sources of doubt 

 and perplexity would ever be removed. On 

 the contrary, they might, perhaps, go on 

 augmenting in number, altho our confidence 

 in the wisdom o'f the plan of Nature should 

 increase at the same time; for it has been 

 justly said that the greater the circle of 

 light the greater the boundary of darkness 

 by which it is surrounded. LYELL Princi- 

 ples of Geology, bk. ii, ch. 29, p. 493. (A., 

 1854.) 



2334. MYSTERY REMAINS EVEN 

 TO THE MONIST The Riddle of the Uni- 

 verse Unread. We grant at once that the 

 innermost character of Nature is just as 

 little understood by us as it was by An- 

 aximander and Empedocles twenty-four hun- 

 dred years ago, by Spinoza and Newton two 

 hundred years ago, and by Kant and Goethe 

 one hundred years ago. We must even grant 

 that this essence of substance becomes more 

 mysterious and enigmatic the deeper we 

 penetrate into the knowledge of its attri- 

 butes, matter and energy, and the more 

 thoroughly we study its countless phenom- 

 enal forms and their evolution. We do not 

 know the " thing in itself " that lies be- 

 hind these knowable phenomena. HAECKEL 

 Riddle of the Universe, concl., p. 380. (H., 

 1900.) 



2335. MYSTERY, SCIENTIFIC A 

 Zone of Darkness The Unknown Every- 

 where Surrounds the Known. Lest this 

 proclamation of mystery should seem alarm- 

 ing, let us add that this mystery also is sci- 

 entific. The one subject on which all sci- 

 entific men are agreed, the one theme on 

 which all alike become eloquent, the one 

 strain of pathos in all their writing and 

 speaking and thinking, concerns that final 

 uncertainty, that utter blackness of dark- 

 ness bounding their work on every side. 

 If the light of Nature is to illuminate for 

 us the spiritual sphere, there may well be a 

 black unknown, corresponding, at least at 

 some points, to this zone of darkness round 

 the natural world. DKUMMOND Natural Law 

 in the Spiritual World, int., p. 25. (H. Al.) 



2336. MYSTERY SOLVED Comets 1 

 Tails Not Ethereal, but Subject to Ordinary 

 Laws of Matter. The mystery of comets' 

 tails has been to some extent penetrated; 

 so far, at least, that by making certain 

 assumptions strongly recommended by the 

 facts of the case their forms can be, with 

 very approximate precision, calculated be- 

 forehand. We have, then, the assurance 



^that these extraordinary appendages are 

 composed of no ethereal or supersensual 

 stuff, but of matter such as we know it, 

 and subject to the ordinary laws of motion, 

 tho in a state of extreme tenuity. This 

 is unquestionably one of the most remark- 

 able discoveries of our time. CLERKE His- 

 tory of Astronomy, pt. ii, ch. 11, p. 417. 

 iBl., 1893.) 



2337. 



Electric Repulsion 



the Producing Cause of Comets' Tails Con- 

 flict of Forces. It is perfectly well ascer- 

 tained that the energy of the push or pull 

 produced by electricity depends (other things, 

 being the same) upon the surface of the 

 body acted on; that of gravity upon its 

 mass. The efficacy of solar electrical re- 

 pulsion relatively to solar gravitational at- 

 traction grows, consequently, as the size of 

 the particle diminishes. Make this small 

 enough, and it will virtually cease to gravi- 

 tate, and will unconditionally obey the im- 

 pulse to recession. This principle Zollner 

 was the first to realize in its application 

 to comets. It gives the key to their con- 

 stitution. Admitting (as we seem bound 

 to do) that the sun and they are similarly 

 electrified, their more substantially aggre- 

 gated parts will still follow the solicitations 

 of his gravity, while the finely divided par- 

 ticles escaping from them will, simply by 

 reason of their minuteness, fall under the 

 sway of his repellent electric power. They 

 will, in other words, form " tails." Nor is 

 any extravagant assumption called for as 

 to the intensity of the electrical charge 

 concerned in producing these effects. Zoll- 

 ner, in fact, showed that it need not be 

 higher than that attributed by the best 

 authorities to the terrestrial surface. 

 CLERKE History of Astronomy, pt. ii, ch. 11, 

 p. 418. (BL, 1893.) 



2338. Hospitals No 



Longer Charnel-houses Exclusion of Bac- 

 teria Helps Surgeon and Patient. It 

 was these organisms [bacteria] acting in 

 wound and abscess which so frequently con- 

 verted our hospitals into charnel-houses, and 

 it is their destruction by the antiseptic sys- 

 tem that now renders justifiable operations 

 which no surgeon would have attempted a 

 few years ago. The gain is immense to the 

 practising surgeon as well as to the patient 

 practised upon. Contrast the anxiety of 

 never feeling sure whether the most brilliant 

 operation might not be rendered nugatory 

 by the access of a few particles of unseen 

 hospital-dust, with the comfort derived from 

 the knowledge that all power of mischief 

 on the part of such dust has been surely 

 and certainly annihilated. TYNDALL Float- 

 ing Matter of the Air, essay 5, p. 287. (A., 

 1895.) 



2339. MYSTERY SURROUNDS 

 FACTS OF SCIENCE The Great Ice Age Un- 

 explained. It follows [from previous ex- 

 planations] that the low temperature which 

 undoubtedly prevailed during the Glacial 

 Epoch has not yet received any satisfac- 

 tory explanation. Each one that has been 

 proposed is either inadequate or attended 

 by grave difficulties. It is therefore prob- 

 able that some factor which is essential for 

 the complete solution of the problem is as 

 yet undiscovered, or, at any rate, the im- 

 portance of one which is already known has 



