bridge, and Leverrier, of Paris, came to the 

 conclusion that there was a planet of considerable 

 importance very much outside the orbit of 

 Uranus, which caused these pert lu-bations, and very- 

 careful calculations led them at last to the 

 conclusion that the new planet, which then had 

 no name, would be found in a certain part of the 

 heavens at a certain time, and so nearly did 

 those two astronomers work out the problem that 

 they only differed by one degree as to the position 

 of the planet. That was one of the juost astound- 

 ing instances of dogged perseverance, of careful 

 calculation and research, and of unbounded 

 faith in the reliability of the great law of gravity 

 which Newton had enunciated long before. 

 Then came its actual discovery, which was made 

 independently by Adams and Leverrier. The 

 orbit of that new planet which was afterwards 

 called Neptune, was about Itio of our years. 

 It was not a brilliant or conspicuous object, 

 although considerably hirger than our earth. On 

 this particular occasion, however, Galle at Berlin 

 saw the planet within a short distance of where 

 they expected to find it. There were in those 

 days few railways and no telegraphs, but in oiu- 

 time the news of such a discovery would have 

 been promptly communicated to the whole world. 

 Truly, it was a wonderful example of discovery 

 by two persevering scientists, and of their actually 

 assigning to it its mass and diameter — a marvel- 

 lous instance of what science was capable. So 

 much for the discovery of Neptune. Another 

 remarkable thing was that the time kept by planets, 

 moving at a tremendous i-ate. was perfectly accu- 

 rate. There was no such thing in Nature as 

 ■" near to " or " about " so-and-so. They were Tip 

 to time to the merest fraction of a second. Very 

 few of those present probably were able to count 

 ten in a second, but what about a body like our 

 earth which would flash through space at a speed 

 of nineteen miles in a second ! That was almost 

 incomprehensible, but yet that was not the highest 

 rate of speed. Other stars were said to move ten 

 times as fast as our earth. 



He now came to the researches to which he 

 wished to call attention more part iculax-ly— re- 

 searches which were now in hand and a subject of 

 -enormous interest to all of us, because they tended 

 to the uprooting of certain views as to the nature of 

 electricity and to the reconsideration of the laws of 

 chemistry itself. He referred to the new element 

 — for an element it is — Radium. There was a 

 singular coincidence between the discovery of 

 Uranus, and, on the other hand, the discovery of 

 Eadium through the instrumentality of a mineral 

 containing Uranium. It was a coincidence and 

 nothing but a coincidence, although he strongly 

 suspected that it was named after the planet 

 Uranium compounds were very remarkable in 

 character and its chief source was known mineral- 

 ogically as Pitchblende. Uranium compoimds 

 were used very extensively in the laboratory, in 

 fact he did not think they could possibly do with- 

 out them as reagents. It was also known for its 

 singularly beautiful fluorescent qualities, but was 

 looked upon as somewhat unusual in its behavioui-. 

 Its atomic weight was considerable— ^it was prob- 

 ably one of the heaviest atoms known—and thePitch- 



blende mineral in whicli it was found was an im- 

 inviting, dull-looking material with but little 

 external beauty about it. It also existed in 

 Uranite. We were a great deal in the dark as to 

 the constitution of Uraniimi. The aspect of its 

 salts when heated before the spectroscope was 

 very remarkable indeed, and this attracted the 

 attention of the late Professor Curie, of Paris, and 

 up to the time of his tragic death in the boule- 

 vards through being run over hy a motor-car, he 

 must have worked untiringly upon it. and also 

 have received great assistance from his wife, 

 Madame Curie, who was the first lady to be 

 honoured by being made a member of the 

 Chemical Society. Madame Ciu-ie had worked 

 upon tons of Pitchblende, an<l the net result was 

 six or eight grains of that precious Radium as a 

 result of her toil. Uraniiuii was one of the first 

 radiant minerals known to science, but Radium 

 was probably a million times as powerful. The 

 Radium emanations were being thoroughly inves- 

 tigated, and only within the last twelvemonth 

 scientists had given it as their opinion that in 

 Ratlium we possessed a most powerfiU and subtle 

 agent. Within the last few months solutions 

 of copper had been exposed to the rays 

 from a small quantity of Radimn, 

 salt, with the result that two elements 

 if not three, had turned up which were 

 not there before — lithium and sodium salts. Not 

 only so, but there was a suspicion that uranium 

 itself was a compound of lead and heliimi. Helium 

 was discovered many years before radixuu. It was 

 one of the recognised gases in the sun's 

 atmosphere, and was credited with very remark- 

 able ijroperties indeed. The discovery of helium 

 led to that of many other elements, and it was 

 now suspected that the curative effects of certain 

 minenU natural waters were due to those rarer 

 gases, which probably were not available at a 

 distance from the springs. He threw that out as 

 an instance of the medical value of some'of these 

 discoveries. The Rr>ntgeu rays, although not 

 derived fi'om Radium, were similar in character, 

 in that they contained radiant matter which 

 penetrated solid bodies by mere exposure to the 

 rays. But even that was not all. We were now 

 informed by some of oiu- foremost physicists that 

 electricity must be looked upon no longer as a 

 fluid, but as helping to constitute a material of 

 which chemical atoms are built up in the form of 

 eleeti-ons. That was to say that what we had 

 hitherto called atoms and looked upon as incapable 

 of division — something a thousand times smaller 

 than the finest microscope could render visible — 

 were really, each of them, made up of thousands 

 if not tens of thousands of electrons. As to what 

 they were we knew nothing, except that they 

 seemed to be tenanted by electricity of high 

 tension. Chemical calculations had hitherto been 

 founded upon the atomic theory which Dalton 

 discovered that the atoms varied from one an- 

 other in their weight and only in 

 their weight, and that the combining 

 power of these atoms was a small multiple of their 

 weight. Whether atoms should now prove to 

 be divisible or not, woiUdnot effect the value of the 

 atomic theory as a working theory which had 



