272 



SCIENTIFIC NEW^S. 



[Mar. 



fifty-eight scholars, it contained 0-620, 0-636, and 0-557 

 per cent., or between seven and eight times as much. 

 Besides this there are the bodily exhalations, which are 

 still worse than the carbonic acid. The practical lesson 

 taught by these facts is, that wherever school accommo- 

 dation is at all limited, the pupils should go out for a run 

 between each lesson. 



Electric Lighting and Sewage Disposal. — A very 

 novel installation of the electric light has been recently 

 carried out by Messrs. Woodhouse and Rawson at the 

 Crossness pumping station, where the huge depositing 

 tanks for sewage are lighted up. A great deal of diffi- 

 culty was experienced in carrying out the contract, as 

 the men had to work in long waterproof boots in the 

 midst of the floating sewage matter ; the vapour and 

 sewer gas rotted all the bindings on the insulators, until 

 at last wire covered with gutta-percha was used. The 

 lamps are all enclosed in water-tight lanterns, and hang 

 from the springs of the arches. Formerly the men work- 

 ing in these tanks had each to carry three or four candles 

 about with him, affixed to the end of a stick, and these, 

 in consequence of the bad atmosphere, burnt very badly. 

 — Electrical Review. 



Safety from Earthquakes. — M. Zaborowski, in La 

 Justice, expounds the views of M. Louis Tudor on this 

 subject. He considers it important to select localities 

 which have been free from shocks from time immemorial. 

 He gives as an instance Nola, near Naples, Quito, Puembo, 

 or Tumbaco, in New Granada, which have all escaped 

 successive earthquakes, whilst adjacent towns or villages 

 have been ravaged or destroyed. He mentions that all 

 the places which have enjoyed such immunity are built 

 on or near deep wells, mines, caverns or natural clefts in 

 the subjacent strata. He refers also to the recognised 

 fact that in the deep mines of Chili the earthquake 

 shocks which agitate the surface are not noticed. M. 

 Zaborowski thinks that deep cavities can serve only to 

 check the propagation of the earthquake-waves, so that 

 their efficacy depends on their relative position. 



Exploration in the Alaska Regions. — The party 

 sent by the Dominion Government to explore the country 

 adjacent to the Alaska boundary, has returned to Victoria, 

 having collected much geological, geographical, and 

 general information about the country, which is far from 

 being the Arctic region it is sometimes represented to be. 

 The point reached by Dr. Dawson was the junction of 

 the Lewis and Pally rivers, about 1,000 miles north of 

 Victoria. The flora in this locality differed Httle from 

 that on the banks of the Eraser. A stretch of open 

 grassy country exists along the streams tributary to the 

 Yukon. No areas of tundra, or frozen swamps, such as 

 are to be met with in the interior of Alaska, were dis- 

 covered by the expedition. Dr. Dawson is of opinion 

 that the whole country, from Gassier to the vicinity of 

 Forty-one Mile Creek, on the Yukon river — which is 

 near the eastern boundary of Alaska — will yield more or 

 less gold in placer deposits. This would constitute a 

 gold-bearing region fully 500 miles in length, and of in- 

 definite width. 



The Perspiration. — According to the Lancet the re- 

 sult of elaborate research made by M. Peiper yields the 

 following conclusions : — The perspiration is more con- 

 centrated on the right side of the body. This observa- ! 



tion is in accordance with that of Reinhardt ; it would 

 be interesting to know whether the opposite was the case- 

 in the left-handed. The palm of the hand sweats four 

 times more than the skin of the chest, and the cheeks 

 one and a half times as much. There is a slow in- 

 crease in the sweat in the afternoon, especially obvious 

 from eight to twelve o'clock at night. After midnight 

 there is a diminution. Feeding has but little influence 

 on this function. Elevation of the surrounding tem- 

 perature increases the perspiration, and variations of the 

 hygrometric state of the atmosphere have an immense 

 influence on the function. The quantity of water 

 evaporated in a quarter of an hour from a cutaneous 

 surface 25 centimetres square, in a normal individual, is 

 about -176 of a gramme. In infants the quantity is 

 generally less than in adults. The weight of the body 

 and sex have no marked influence on the perspiration. 



Lignite. — Although briquettes are rapidly gaining 

 favour in Germany, especially as fuel for industrial pur- 

 poses, the use of lignite is, according to Industries, also 

 extending. The Berlin Coal Company have for some 

 time past been raising lignite from a mine in the province 

 of Brandenburg, near the Teupitz Lake, and are now 

 about to extend their operations. They have just 

 acquired mining rights over about 10,000 acres of land, 

 and in addition to the first shaft, which was sunk some 

 time ago, another shaft is about to be commenced. In 

 connection with this work some important orders for 

 pumping engines and mining appliances generally will 

 be given out. The coal is of an excellent quality, very 

 dense, hard, and is obtained in large pieces. A good 

 market is secured for it at the start by the neighbouring 

 brick works of Morzen, where there are thirty-two 

 Hoffmann kilns, requiring annually about 300,000 tons of 

 coal. The district has exceptional transport facilities, 

 there being two waterways from the lake to Berlin, in 

 addition to various railway lines. Owing to this compe- 

 tition, freights to Berlin rule as low as is. per ton; that 

 is, about the same charge as is made by the railway com- 

 panies for delivery within the town. 



Engraving with Mercury and its Salts. — According 

 to the Memorial Indvistrielle, if a well-polished and clean 

 plate of zinc be taken, and a design traced thereon with 

 mercury, the design will appear in brilliant white upon 

 the grey background of the zinc. An intaglio plate can 

 be obtained by plunging the plate into a bath containing 

 100 parts of water and two parts at least of nitric acid. 

 The action of the acid is very rapid, and for a long time 

 only attacks the parts touched by the mercury. When 

 deep enough it can be used for lithographic work. If, 

 instead of nitric, hydrochloric acid is used, the contrary 

 effect takes place. The unaffected zinc is strongly 

 attacked, and the traces of the mercury give a relief 

 plate, which can be used for ordinary typographical work. 

 If the operator does not wish to draw upon zinc, the de- 

 sign can be traced upon paper with biniodide of mercury. 

 The sheet of paper being then applied for two hours to a 

 plate of zinc, the drawing is sharply reproduced in white 

 lines of amalgam on the grey surface of the metal, just 

 as if it had been traced directly. The same result is 

 obtained if the design be traced upon paper with a sticky 

 substance (ink containing gum or sugar), and if it be 

 dusted over with a mercury salt in fine powder. On 

 dusting off" the surplus and applying the sheet containing 

 the design to a plate of metal, the same result is obtained. 



