July 27, 1883.] 



» KNO\VLEDGE ♦ 



51 



torturing. Any cruelty was justified by its perpetrators 

 when the object in view was the vindication of the majesty 

 of God ; and not until the advancing intelligence of men 

 recoiled against the popular explanations of witchcraft and 

 lycanthropy were the laws against both repealed. 



Those explanations were survivals of savage mental 

 philosophy blended with a crude theology. To the savage, 

 all diseases are the work of evil spirits. If a man hurts 

 himself against a stone, the demon in the stone is the 

 cause. If the man falls suddenly ill, writhes or shrieks in 

 his pain, the spirit which has smuggled itself in with the 

 food or the drink or the breath is twisting or tearing him ; 

 if he has a fit, the spirit has flung him ; if he is in the 

 frenzy of hysteria, the spirit within him is laughing in 

 fiendish glee. And when the man suddenly loses his 

 reason, goes, as people say, " out of his mind," acts and 

 looks no longer like his former self, still more does this 

 seem the work of an evil agent within him. It is kindred 

 with the old belief that the sickly and ugly infant had 

 been left in the cradle by the witch in place of the child 

 which she had stolen before its baptism.* And the thing to 

 do is to find some mode of conjuring or frightening or 

 forcing the demon out of the man, just as it became a 

 sacred duty to watch over the newly-born until the sign of 

 the Cross had been made on its forehead, and the regene- 

 rating water sprinkled over it. 



"Presbyter is but old priest writ large." And the 

 theory of demoniacal agency was but the savage theory in 

 a more elaborate guise. To theologians and jurists it 

 was a sufficing explanation ; it fitted in with the current 

 notions of the government of the universe, and there was 

 no need to frame any other. Body and mind were to them 

 as separate entities, as they are to the savage and the 

 ignorant. Each regarded the soul as independent of the body, 

 and framed his theories of occasional absence therefrom 

 accordingly. But science has taught us to know ourselves 

 not as dual, but as one. She lays her finger on the 

 subtle, intricate framework of man's nervous system, 

 and finds in the derangement of this the secret of 

 those delusions and illusions which have been so prolific 

 in agony and suffering. She makes clear how the yielding 

 to morbid tendencies can still foster delusions, which, if no 

 longer the subject of pains and penalties in the body 

 politic, are themselves ministers of vengeance in the 

 body where they arise. And in the recognition of a 

 fundamental unity between the physical and the mental, 

 in the healthy working of the one as dependent on the 

 wholesome care of the other, she finds not only the remedy 

 against mental derangement and all forms of harmful 

 excitement, but also the prevention which is better an 

 cura 



The Luminosity op Heated Gases. — Dr. Werner 

 Siemens has recently demonstrated, by means of his rege- 

 nerative furnace, that highly heated gases do not emit liglit 

 The furnace employed was that of his brother, the glass 

 manufacturer of Dresden, which gives a temperature of 

 1,500 deg. to 2,000 deg. Centigrade. The interior of the 

 furnace was watched through sight - holes, and not the 

 least light met the eye from the highly-heated air of the 

 furnace. It therefore appears that all light from h' ted 

 gas must come, not from the gas, but some solid rad. .ting 

 impurity. Observations with a thermopile also seem to 

 show that no heat either is radiated by pure gases at a high 

 temperature. — Engineering. 



* Spenser says : — 

 " Such, men do chanfjclings call, so changed by fairies' theft." 



SPOTS OX THE SUN. 



By Richakd A. Proctor. 



JUST now, when there are many spots on the sun, when 

 new spots are continually forming, and when, in fine, 

 that state of disturbance which is indicated by solar spots 

 seems to be nearly at its height, it may be interesting to 

 consider what the solar spots probably are, how they are 

 generated, how they affect surrounding parts of the sun's 

 surface, and how, after passing through the various stages 

 of their existence, they come eventually to disappear. The 

 inquiry is one of much difficulty, for the phenomena pre- 

 sented by spots are very complex and perplexing. We 

 shall have to look at the subject from every available point 

 of view, to see whether, by combining together all that 

 is known either about the spots themselves or about 

 phenomena related to them, we can determine their real 

 nature. 



In the first place, it will be well to consider what lies, 

 probably, underneath the visible solar surface. We can 

 then pass to the surface itself, thence to what lies outside 

 that surface, until we reach the limits beyond which, so 

 far as can be judged, we are not likely to obtain any in- 

 formation bearing directly on the solar spots. 



Now, it is rather singular that the first direct informa- 

 tion obtained by man respecting the sun's interior should 

 have been derived from the study of the earth's crust 

 beneath his feet. 



Yet that has, in effect, been the case. The earth's crust 

 tells us in unmistakable terms of tens of millions of years 

 during which the sun has been at work pouring his rays of 

 light and heat upon the earth as now — it may be in greater, 

 it may be in smaller amount at one time or at another, but 

 doing — which is all we need consider — an amount of sun- 

 work corresponding to tens of millions of years' work at his 

 present rate of emission of light-waves and heat-waves. 

 Dr. CroU tells us, and Sir Charles Lyell adopted the state- 

 ment as within the truth, that the earth's crust thus speaks 

 unmistakably of at least one hundred millions of years of 

 sun-work. 



Now, the source of the solar light and heat is to be found 

 in gravitation — that mysterious force which explained the 

 mystery of the planetary movements, but presents in 

 itself a far greater mystery. It explains also the mystery 

 of light and heat which but for gravity would never have 

 existed. The gathering-in of the sun's mass to its present 

 volume, whatever that volume may be, generated the 

 light and heat which the sun has emitted in the past, and 

 the same process continuing will generate as the sim's 

 volume continually diminishes the light and heat which 

 doubtless he will cintinue to emit for many millions of 

 years yet to come. 



But if we measure the sun's volume, his mass being 

 known, by the length of time during which he has been at 

 work as at present, we find that, however vast we suppose 

 the region of space to be throughout which his mass was 

 formerly distributed, he must — judging from the work he 

 has already done — have a volume very much less tlian he 

 appears to have. For if he had gathered in his mass from 

 a region of space practically infinite, until it was uniformly 

 distributed throughout a volume such as the solar photo- 

 sphere encloses, the heat resulting from this process of for- 

 mation would not be equi\alent to more than some twenty 

 millions of years' supply of heat at the present rate of 

 emission. But the earth alone tells us of at least one 

 hundred millions of years of such emission of heat Now, 

 I think we may safely set aside Dr. Croll's explanation that 

 the sun's heat might in part have been derived from the 



