72 



NATURE 



[March 2;, 1919 



and it is evident that the focus was at a slight depth. 

 Among the after-shocks was one of less, but still 

 ruinous, intensity, which occurred on April 27 at 

 2.30 p.m. (G.M.T.)- 



Mr. R. M. Deejley has sent us a copy of a paper 

 contributed by him to the Philosophical Magazine for 

 March, 19 18, in which he discusses the temperature 

 distribution in a cyclonic depression, and puts forward 

 a hypothesis as to .the causation of these depressions. 

 Upper-air research by means of sounding balloons has 

 shown that in the troposphere the core of a cyclone 

 is cold relatively to the surrounding air, whereas at 

 greater heights, in the stratosphere, the reverse is the 

 case, the air being relatively warm. It is suggested 

 that this warmth probably extends to the confines of 

 the atmosphere. The author considers that the 

 air which flows spirally inwards in the lower layers 

 rises in the central region of the cyclone to great 

 heights, flowing outwards in the higher levels of the 

 stratosphere. This circulation being postulated, it 

 remains to find some means by which the column of 

 rising air in the stratosphere may be warmed, and 

 this Mr. Deeley ascribes to the action of a pencil of 

 high-velocity cosmic matter which strikes and heats 

 the outer part of the atmosphere in a localised patch. 

 The heating is regarded as being produced rapidly and 

 as dying away slowly. According to this theory, 

 cyclones must travel with the winds of the upper 

 atmosphere, which carry the heated core with them. 

 No attempt is made to explain how a cyclone can 

 persist for days, or even weeks, as it travels over the 

 surface of the earth. 



At a meeting of the Institution of Civil Engineers 

 on March 12 three papers were read on electric welding 

 developments. There are three systems in general use. In 

 "spot" welding the metals to be soldered together are 

 placed in contact and an electric current sent between 

 them. This method is rapid and efficient, and is 

 easily performed by unskilled labour. In "seam" or 

 "line" welding, mechanically driven roller electrodes 

 are used; and in the "carbon-arc" process the metal is 

 melted by means of the electric arc. It was pointed 

 out that electric welding would be particularly helpful 

 in the automobile industry, as crank-shafts, broken or 

 worn teeth of gear-wheels, and gear-cases can rapidly 

 be renovated. In shipbuilding it was stated that elec- 

 tric-arc welding has proved successful for forging, 

 riveting, and caulking. It has been found possible to 

 join thick steel plates by welding more economically 

 than by riveting. Experiments showed that in the 

 case of butt-welds the tensile strength of the joints 

 was from 90 to 95 per cent, of that of the solid plate. 

 In the "carbon-arc" process the carbon rod formerly 

 used has now been replaced by an iron welding 

 pencil, which is found to be far more suitable. 



The March issue of the Geographical Journal con- 

 tains a paper by Mr. E. A. Reeves, the map curator 

 of the Royal Geographical Society, on "A Trans- 

 formation of the Magnetic Dip Chart." The trans- 

 formation carried out by Mr. Reeves consists in 

 drawing lines through those places on the earth's 

 surface at which the axis of the dip-needle makes 

 equal angles with tne axis of the earth instead of with 

 the horizontal plane through the place of observa- 

 tion. This plan gives more regular lines, which ap- 

 proximate to circles having an axis inclined at 3° to 

 5° to that of the earth.. In a contribution to the 

 discussion on the paper Dr. Chapman pointed out 

 that whatever axis were taken as that from which to 

 measure the inclination of the dip-needle, _ the curves 

 of equal inclination would approximate to circles about 

 an axis between that chosen and the magnetic axis, 



NO. 2578, VOL. 103] 



! so long as the earth approximated to a uniformly 

 i magnetised sphere. Dr. Chree also pointed out how 

 closely the earth corresponds with a sphere uniformly 

 magnetised about an axis inclined at 12° to the geo- 

 graphic axis. The paper and discussion point to the 

 desirability of taking as the axis of reference the 

 magnetic rather than the geographic axis of the earth. 



"Experiments with Clay in its Relation to Piles" 

 was the subject of a paper by Mr. A. S. E. Ackermann 

 read before the Society of Engineers on March 10. 

 The experiments described deal on a small scale with 

 the resistance of clay to penetration by discs, pyramids, 

 and cylinders. In one test a cylinder of clay 2 cm. 

 in diameter and 68 cm. in length, fixed at one end 

 and twisted at the other through 373°, recovered when 

 released through 32°, which is taken to be a proof of 

 the elasticity of clay. The resistance to penetration 

 (without shock) increases as the water-content 

 diminishes. If W+w is the resistance to penetration 

 and V the volume of penetration, then for pyramids 

 V = a(W + w)'*, where n is about 1-5. In the case of 

 discs at critical loads the disc started and continued 

 to sink in the clay, the pressure, taken to be 

 the pressure of fluidity, being on the average 

 587 grams/cm.^, the water-content being 29 per cent. 

 The general conclusions are : — (i) For tapered bodies 

 the load for a given penetration is proportional to 

 the area of surface of contact; (2) it is much greater 

 the less the percentage of water in the clay; (3) the 

 pressure of fluidity is less when the percentage of 

 water is greater; (4) tapered piles support a greater 

 load than parallel-sided piles; and (5) pointed piles 

 are more efficient than blunt. In the application of 

 these results to practice it must be remembered (apart 

 from the small scale of the tests) that the clay with 

 which an engineer deals is less homogeneous than 

 the puddled clay employed; that piles are driven by 

 impact, which disturbs the earth round the pile; and 

 that the important point is not the resistance when 

 driving, but after a period when the earth is more 

 or less resettled. The tests are, however, interesting 

 to physicists and engineers. 



A SUGGESTION was made a few days ago during a 

 sitting of I the Coal Commission that if higher wages 

 were to be paid to miners, manufacturers would be 

 driven to America or Sweden to seek the advantages 

 of water-power. The allusion to Sweden is strikmg 

 testimony to the rapid developments which are now 

 taking place in the hydro-electric installations of that 

 country. Engineering has from time to time pub- 

 lished particulars of these enterprises (reference has 

 also been made to them in these columns), and in its 

 issue of March 7 it has a long article dealing with the 

 impending extension of hydro-electric power schemes 

 under the auspices of the R'oyal Swedish Waterfalls 

 Board. A power station is projected in Lapland with 

 a capacity of 192,500 kw., having its source in the 

 chain of lakes, the lowest of which, Storea Lulea, 

 finds an outlet in the River Lule. The river is about 

 100 miles in length, and debouches into the Gulf of 

 Bothnia, just below the Arctic Circle. Two important 

 falls on 'the river are the Porjus and the Horsprauget. 

 The former has already been utilised to a consider- 

 able extent; the load, so far as three-phase current is 

 concerned, amounts to 15,000 kw., and when certain 

 extensions have been effected will reach double that 

 figure. The Horsprauget project will furnish an addi- 

 tional estimated capacity of 192,500 kw. The falls, 

 of which there are several in series, will be impounded 

 in a single installation by the construction of a high 

 dam, which will have the distinction of being larger 

 than any hitherto constructed in Sweden. It will be 

 I kilometre (iioo yards) long and about 40 metres 



