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ledge 



SCIENTIFIC SIDE-LIGHTS 



1797. KNOWLEDGE MADE PRAC- 

 TICAL Daguerreotype Founded on Old-time 

 Discovery. The fact that certain salts of 

 silver were darkened by exposure to sun- 

 light was known to the alchemists in the 

 sixteenth century, and this observation 

 forms the rudiment from which the whole 

 art has been developed. The application of 

 this fact to the production of pictures be- 

 longs, however, wholly to our own time. In 

 the year 1802, Wedgewood described a mode 

 of copying paintings on glass by exposure to 

 light, but neither he nor Sir Humphry 

 Davy could find any means of rendering the 

 copies permanent. This was first effected in 

 1814 by M. Niepce, of Chalons, but no im- 

 portant results were obtained till 1839, 

 when Daguerre perfected the beautiful proc- 

 ess known as the daguerreotype. Permanent 

 portraits were taken by him on silvered 

 plates, and they were so delicate and beauti- 

 ful that probably nothing in modern pho- 

 tography can surpass them. For several 

 years they were the only portraits taken by 

 the agency of light, but they were very 

 costly, and were therefore completely super- 

 seded when cheaper methods were discov- 

 ered. WALLACE The Wonderful Century, 

 ch. 5, p. 32. (D. M. & Co., 1899.) 



1798. KNOWLEDGE, MAN YET BUT 

 ON THRESHOLD OF" We Are Ancients of 

 the Earth, in the Morning of the Times."* 

 We are in reality but on the threshold 

 of civilization. Far from showing any in- 

 dication of having come to an end, the 

 tendency to improvement seems latterly to 

 have proceeded with augmented impetus and 

 accelerated rapidity. Why, then, should we 

 suppose that it must now cease? Man has 

 surely not reached the limits of his intel- 

 lectual development, and it is certain that 

 he has not exhausted the infinite capabili- 

 ties of Nature. There are many things which 

 are not as yet dreamt of in our philosophy; 

 many discoveries which will immortalize 

 those who make them, and confer upon the 

 human race advantages which as yet, per- 

 haps, we are not in a condition to appreciate. 

 We may still say with our great country- 

 man, Sir Isaac Newton, that we have been 

 but like children playing on the seashore, 

 and picking up here and there a smoother 

 pebble or a prettier shell than ordinary, 

 while the great ocean of truth lies all undis- 

 covered before us. AVEBURY Prehistoric 

 Times, ch. 16, p. 575. (A., 1900.) 



1799. KNOWLEDGE NOT SUFFI- 

 CIENT FOR CONDUCT Right Desire the 

 Chief Need. Right conduct is usually come 



* " To sleep through terms of mighty wars, 

 Arid wake on science grown to more, 



On secrets of the brain, the stars, 

 As wild as aught of fairy lore ; 



And all that elsetlie years will show ; 



" Titanic forces taking birth 



In divers seasons, divers climes, 

 For we are Ancients of tlie earth, 



And in the morning of the timee." 

 TENNYSON The Day-Dream, IS Envoi, st. 1, 11. 9-20. 



short of more from defect of will than defect 

 of knowledge. For the right coordination of 

 those complex actions which constitute hu- 

 man life in its civilized form, there goes 

 not only the prerequisite, recognition of 

 the proper course, but the further pre- 

 requisite, a due impulse to pursue that 

 coarse. On calling to mind our daily fail- 

 ures to fulfil often-repeated resolutions, we 

 shall perceive that lack of the needful de- 

 sire, rather than lack of the needful insight, 

 is the chief cause of faulty action. SPEN- 

 CER Biology, pt. vi, ch. 13, p. 525. (A., 

 1900.) 



1800. KNOWLEDGE OF FIRE UNI- 

 VERSAL AMONG MEN It cannot be said 

 to be satisfactorily proved that there is 

 at present, or has been within historical 

 times, any race of men entirely ignorant of 

 fire. It is at least certain that as far back 

 as the earliest Swiss lake villages and Da- 

 nish shell-mounds the use of fire was well 

 known in Europe. AVEBURY Prehistoric 

 Times, ch. 15, p. 535. (A., 1900.) 



1801. " KNOWLEDGE OF THE CON- 

 STRUCTION OF THE HEAVENS" Tfa! 



Ambition of the Elder Herschel The In- 

 quiring Spirit of Man. When we look 

 around us into the regions which surround 

 the solar system and see the myriads of 

 myriads of stars which are spread through 

 space, it is impossible not to feel strongly 

 the desire to penetrate the mystery of the 

 star-strewn depths. We have learned much 

 respecting the earth on which we live, and 

 not a little of the system to which the earth 

 belongs. We have at least so far solved the 

 problems presented to us by the planetary 

 scheme as to recognize the subordinate posi- 

 tion which our earth holds within it, and 

 that the sun is the mighty ruler whose sway 

 guides all the planets in their courses. But 

 the inquiring spirit of man is not satisfied 

 with these discoveries. No sooner has he 

 learned to regard the earth as but one of a 

 system of worlds circling round the sun, and 

 that that system has such and such propor- 

 tions, and presents such and such forms of 

 motion, than he desires to regard our sun as 

 but one of a system of suns, and to ascertain 

 what may be the nature and the scale of this 

 higher system, what the movements taking 

 place within it. This was the noble prob- 

 lem which the elder Herschel set as the 

 great end and aim of all his labors : " A 

 knowledge of the construction of the heav- 

 ens," he said, towards the end of his won- 

 derful career as an observer, " has always 

 been the ultimate object of my observa- 

 tions." PROCTOR Expanse of Heaven, p. 256. 

 (L. G. & Co., 1897.) 



1802. LABOR ESSENTIAL TO HU- 

 MAN PROGRESS Rigorous Climates Stimu- 

 late Improvement in Conditions and Re- 

 sults of Work Evil with Good. We do not 

 wish to draw upon ourselves the imputation 

 of advocating the inevitable progress of the 

 human race. The world is subject to evil 



