462 



NATURE 



[Sept. 12, 1889 



crack on July 28, and the phenomenon continued until 

 the whole surface was covered with a network of fissures. 

 According to the latest accounts, fifty-three distinct shocks 

 had been felt, only two or three of them being: severe. 

 "Within twelve hours on August 3, thirty-five earthquakes 

 were experienced at Kumamoto, one of which caused 

 the ground to open in no fewer than twelve places. 



THE UNITED STATES ECLIPSE EXPEDITION. 



T^HE Navy Department in Washington is now fitting 



-*■ out an Expedition to Angola, on the west coast of 

 Africa, to observe the total eclipse of the sun which will 

 be visible there on the afternoon of December 22 next. 

 Prof. Todd, of Amherst College, has been appointed chief 

 of the party, a position similar to that which he held two 

 years ago in conducting the Eclipse Expedition to Japan. 



The party, which will be a large one, will leave New 

 York about October i, in a Government cruiser. The 

 natural history department of the Expedition will be under 

 the charge of Dr. Wm. J. Holland, of Pittsburg, who will 

 make large collections and extensive investigations, 

 especially in entomology, which is his special department. 

 He filled a similar position in the Expedition to Japan in 

 1887. Work will be done in many directions, and even 

 if the weather or any accident should render a successful 

 observation of the eclipse impossible, the Expedition will 

 have a great amount of valuable information and collec- 

 tions when it returns. 



After landing at St. Paul de Loanda, 250 miles south 

 of the mouth of the Congo, the Expedition will go 

 about one hundred miles into the interior, in order to be 

 on higher land, and out of the fever belt on the coast. 

 The eclipse, which will occur on December 22, 1889, at 

 about 3 p.m., will be total for a little over three minutes 

 at the station south-east of Loanda. The whole length of 

 the eclipse will be between two and three hours. In 

 photographing its different phases, if the sky is clear, 

 it is hoped that about 150 photographs will be taken, 

 with the largest telescope ever used for photographing an 

 eclipse. This will give an image of the sun about 4^ 

 inches in diameter. Owing to the number of fine instru- 

 ments which have to be carefully transported and 

 adjusted, about two months will be spent at the observa- 

 tion station, and the party will be absent about five or 

 six months altogether. The particular point where it is 

 hoped a settlement may be made is Muxima on the Quanza 

 River. In reply to a question as to the instruments he 

 would take with him, Prof. Todd is reported to have 

 said : — 



"Some of them will be the same as I had in Japan, es- 

 pecially the great telescope, forty feet long, to get pictures 

 of the different stages of the eclipse with. It is the same 

 sort of a telescope that I used in photographing the 

 transit of Venus in 1882 at the Lick Observatory. But 

 photographing the corona is not the main thing nowadays 

 in eclipses. All that has gone by. There are other ques- 

 tions of much more importance than merely to find out 

 how the corona looks. It is a very complex phenomenon. 

 The sources of its light are not known, and the streamers 

 of light are in parts superposed or overlapping. The 

 most important thing to do is to take photographs in such 

 a way that the intensity of the light in every part can be 

 accurately measured, and to photograph the spectrum of 

 as many separate portions of the coronal light as 

 possible. We are making much progress in this direc- 

 tion, but the old methods of eclipse photography in use 

 ten or fifteen years ago yielded very insufficient results, 

 and there is relatively little use in following them up if 

 the more advanced and specialized work is not under- 

 taken. Of course they are good as far as they go. Then 

 I shall have several new devices, which my previous 

 experience, particularly in Japan, has led to the invention 



of. Among other things I have devised a revolving plate 

 holder, which will enable us to get the largest possible 

 number of pictures at the critical moments." 



URANIUM. 



■pXACTLY a century ago— namely, in 1789 — Klaproth 

 *~^ succeeded (says the Times) in isolating from a dark- 

 coloured mineral known as pitchblende a yellow oxide, 

 which, after carefully testing, he pronounced to be the 

 oxide of a new metal. To this metallic substance he 

 gave the name of uranium, so calling it after the planet 

 Uranus, then recently discovered by Herschel, and it 

 was at once classed among the rare metals, and still re- 

 mains so. Its rarity is indicated by its market price, 

 which is about ^2400 per ton. There are several oxides 

 of this metal ; but the best known and most important 

 is the sesquioxide, which forms a number of beautiful 

 yellow salts. This oxide is largely employed for imparting 

 delicate golden and greenish yellow tints to glass, while 

 the protoxide is much used in producing the costly black 

 porcelain. Uranium is also found to be useful in certain 

 photographic processes as a substitute for the chloride of 

 gold ; but its rarity and consequent high price have 

 hitherto caused its application to be very limited, although 

 there are uses other than those already named to which 

 it could be put if it were less scarce and less costly. It 

 is found in Cornwall, Saxony, and Bohemia ; but up to 

 the present time it has only been met with in isolated 

 pockets and patches. The centenary of its discovery by 

 Klaproth has, however, been marked by the finding of a 

 continuous lode at the Union Mine, Grampound Road, 

 Cornwall, which is believed to be the only known lode in 

 the world. This discovery is regarded as unique in the 

 history of the metal, for the lode is what is known as 

 a true fissure vein, and the ore is found to contain an 

 average of 12 per cent, of the pure metal, the assays 

 going up as high as 30 per cent, in some parts of the lode. 

 Several tons of the ore have already been raised and 

 sold, fetching high prices. The lode traverses the mine 

 from north to south, and the uranium occurs in it chiefly 

 as a sesquioxide. It is anticipated that the present dis- 

 covery will enable two important applications of the 

 metal to be followed up. The first is as a substitute for 

 gold in electroplated ware, inasmuch as with platinum 

 and copper it forms two beautiful alloys, each having the 

 appearance of gold, and the former also resisting the 

 action of acids. The second application-is in connection 

 with electric installations, where its usefulness consists 

 in its high electrical resistance. The mineral deposits 

 generally at the Union Mine are of an exceptional 

 character, comprising, in addition to uranium, magnetic 

 iron, silver lead, tin, copper, ochre, and umber. 



THE BRITISH ASSOCIATION. 



Newcastle, Tuesday Night. 

 T T is impossible at this stage to say what will be the 

 -^ character of the third Newcastle meeting, so far as 

 numbers are concerned. In one quarter I am informed 

 it is not expected that the attendance will be above the 

 average, while another authority, who ought to know, 

 assures me the numbers will be greater than was the case 

 even at the Manchester meeting. For it should be re- 

 membered that, until that meeting, Newcastle topped the 

 record so far as numbers go. To judge from the aspect 

 of the Reception Room, not many people have yet arrived, 

 though doubtless they will come in by later trains, and to- 

 morrow morning. So far as I have been able to learn, 

 very few foreign men of science of distinction are ex- 

 pected. Universal regret is expressed that the serious 

 illness of Dr. Burdon Sanderson will prevent his taking 



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