Seit. 5, 1884.] 



♦ KNOWLEDGE ♦ 



197 



Russian finances -will permit the alternative proposal of 

 cutting a purely artificial canal by the shortest line, at an 

 estimated expense of 15 to 20 million roubles. 



There are few particulais in which the best atlases of 

 the present day differ more from those published twenty-five 

 years ago than iu the information they give us respecting the 

 submerged portions of the globe. The British Islands, with 

 the fifty and one hundred-fathom lines of soundings drawn 

 round them, seem to bear a different relation to each other 

 and to the Continent than they did before. The geography 

 of the bed of the ocean is scarcely less interesting than that 

 of the Continents, or less important to the knowledge of 

 terrestrial physics. Since the celebrated voyage of H.M.S. 

 Challeni/er, no marine researches have been more fruitful 

 of results than those of the Talisman, and the Dacia. The 

 first was employed last year by the French Government to 

 examine the Atlantic coasts from Rochefort to Senegal, and 

 to investigate the hydrography and natural history of the 

 Cape Verde, Canary, and Azores archipelagos. The other 

 ship, with her companion, the International, was a private 

 adventure, with the commercial purpose of ascertaining the 

 best line for a submarine telegraph from Spain to the 

 Canaries. These two last made some .550 soundings 

 and discovered three shoals, one of them with less 

 than 50 fathoms of water over it, between the Con- 

 tinent of Africa and the island. If we draw a 

 circle passing through Cape Mogador, Teneriffe, and 

 Funchal, its centre will mark very nearly this submarine 

 elevation ; the other two lie to the north of it. The TnUs- 

 man found in mid-ocean but 1,640 fathoms, among sound- 

 ings previously set down as over 2,000 fathoms. Our 

 knowledge then of the bed of the Atlantic, and of the 

 changes of depth it may be undergoing, is but iu its 

 infancy ; and we have only to reflect what sort of oro- 

 graphic map of Europe we could hope to draw, by sounding 

 lines dropped a hundred miles apart from the highest 

 clouds, to be conscious of its imperfection. But this 

 knowledge is accumulating, and whether revealing at one 

 moment a profound abyss, or at another an unsuspected 

 summit : marvels of life, form, and colour, or new and 

 pregnant facts of distribution ; it promises for a long time 

 to come to furnish inexhaustible interest. 



Canada comprises within its limits two spots of a physical 

 interest not surpassed by any others on the globe. I mean 

 the pole of vertical magnetic attraction, commonly called 

 the magnetic pole, and the focus of greatest magnetic force; 

 also often, but incorrectly, called a pole. The first of these, 

 discovered by Ross in 1835, was revisited in May 1847 by 

 officers of the Franklin Expedition, whose observations 

 have perished, and was again reached or very nearly so by 

 McClintock in 1859, and by Schwatka in 1879 ; neither of 

 these explorers, however, was equipped for observation. 

 The utmost interest attaches to the question whether the 

 magnetic pole has shifted its position in fifty years, and 

 although I am far from rating the difficulty lightly, it is 

 probably approachable o\erland, without the great cost of 

 an Arctic expedition. The second has never been visited 

 at all, although Dr. R. Bell, in his exploration of Lake 

 Nipigon was within 200 miles of it, and the distance is 

 about the same from the Rat Portage. It is in the neigh- 

 bourhood of Cat Lake. 



One of the finest feats of mountaineering on record was 

 performed last year by Mr. W. AV. Graham, who reached 

 an elevation of 23,500 ft. in the Himalayas, about 2,900 ft. 

 above the sitmmit of Chimborazo, whose ascent by Mr. 

 Whymper, in 1880, marked an epoch in these exploits. 

 Mr. Graham was accompanied by an officer of the Swiss 

 army, an experienced mountaineer, and by a professional 

 Swiss guide. They ascended Kabru, a mountain visible 



from Darjeeling, lying to the west of Kanchinjunga, 

 whose summit still defies the .strength of man. 



The reported outbreak of a new volcano in the northern 

 part of West Australia, on August 25, 1883, in connection 

 with the great eruption of the Sunda Straits, has not, as 

 far as I know, been verified ; but the graphic description 

 of the natives : "Big mountain burn up. He big one sick. 

 Throw him up red stuff, it run down side and burn down 

 grass and trees," seems to leave little doubt of the reality 

 of the occurrence. 



THE ELECTRIC LIGHT IN THE 

 MECHERNICH MINES.* 



THE electric-light installation at the Mechernich Mines 

 in its once volcanic Eifel district in Rhenish Prussia, 

 has now had a fair trial for more than three years, and has 

 proved a complete success. The expectation that it would 

 both facilitate the operations and increase their security, 

 has fully been realised, and an extension of the i)lant is 

 now being carried out. Messrs. Siemens and Halske, of 

 Berlin, undertook the work, which was superintended on 

 their behalf by Mr. Boeddinghaus. An open working 

 2,000 ft. long, 1,000 ft. wide, and over 300 ft. deep, in 

 which 300 men and 20 horses are continually occupied, 

 was first to be supplied with the electric light. This part 

 of the mine is excavated in steps, the horizontal terraces 

 being provided with rails. Ordinary lamps in globes on 

 poles were out of the question, as blasting operations 

 continue throughout the day, and the shots would 

 soon have made havoc of the lamps. After several 

 trials two powerful lamps, of 3,000 candles each, were 

 erected at the upper margin of the pit, where they were 

 fairly out of the reach of the projected stones ; and reflec- 

 tors "were fixed to throw the light down upon the steps. 

 To find the proper positions for these powerful lamps and 

 to avoid too dark shadows caused some difficulty. But the 

 illumination was finally rendered most efficient, and the 

 open pit, with the light playing on the whitish grey rock, 

 aflbrds a fine spectacle. As any interruptions, even for 

 short periods, such as those occupied in renewing the lamp 

 carbons, would be dangerous, the whole plant is double, 

 each lamp receiving its current from a D;. dynamo. No 

 hitch of any kind has occurred, and the safety of the 

 miners has decidedly been augmented. It was formerly 

 not always possible for the superintendents to see whether 

 the loose mass resulting from the blasting operations 

 had been properly removed, and frequent minor acci- 

 dents arose from the debris falling down upon the miners 

 engaged on the step next below. The work can now be 

 controlled much better than before when petroleum lamps 

 and hand lamps were in use. The cost shows a saving of 

 about 4d. per hour in favour of the electric illumination. 

 The satisfactory results obtained in the open working 

 induced the company to introduce the electric light down 

 in the subterranean galleries. The ore forms little concre- 

 tions of sand and galena scattered all through the rock ; 

 the whole mass has therefore to be brought to day to be 

 disintegrated and sifted, and the mining proceeds in piiraUel 

 and cross galleries, which are constantly being widened 

 until they become 90 ft. in width, and 70 ft. in height, by 

 sometimes 300 ft. in length. The operations in themselves 

 would not require much light if there was not always 

 danger threatening from loosened pieces of rock. Pitch 

 torches were formerly employed to examine the bore- 

 holes and fissures round them after each explosion. 



* From Engineering. 



