84 



NATURE 



[July 21, 19 10 



The problem of determining the vertital motion of the 

 air during a balloon ascent is complicated by the fact that 

 the balloon itself is in motion. Measurement of the varia- 

 tion of the barometric pressure at the balloon has, how- 

 ever, proved a trustworthy means of determining the vertical 

 motion of the balloon, and the further problem of record- 

 ing the relative vertical motion of the air with respect to 

 the balloon appears to have been satisfactorily solved by 

 an instrument described by Mr. P. Ludevig in the 

 Physikalische Zeitschyift for June 15. It consists of light 

 anemometer vanes which can rotate about a vertical axis. 

 The spindle carries a thin, hollow brass cylinder through 

 which six holes are punched, each pair at opposite extremi- 

 ties of a diameter, two near the top, two near the middle, 

 and two near the bottom of the cylinder. The diameters 

 are inclined at 60° to each other. Light can pass through, 

 say, the central pair of holes when they happen to be in 

 the direct line between a source and a moving strip of 

 photographic paper, and a spot is registered. According 

 to the direction of rotation of the cylinder, the spot next 

 registered may be the upper or lower, and the speed of 

 rotation determines the distance between the spots. An 

 examination of the strip allows the speed of the air with 

 respect to the balloon at any instant to be calculated if 

 the speed of the strip is known. 



The Ontario Government announces that the system 

 organised for the distribution of power from the Niagara 

 Kails will be in operation for the supply of Toronto, 

 London, and St. Thomas by the end of the year. The 

 most distant of these places is about 100 miles from the 

 Falls, and the transmission will be at 100,000 volts. The 

 ■electrical energy will be bought from the existing Canadian 

 generating stations by the various municipalities, which 

 will effect the distribution by new transmission lines 

 extending over a wide area. By this means cheap power 

 will be available for manufacturing and agricultural pur- 

 poses, and it is hoped that a network of new tramways 

 will be constructed which will not only improve travelling 

 facilities, but also act as a means of bringing agricultural 

 produce to the towns. A system of distribution of this 

 kind should be of particular value in Canada, seeing that 

 the supply cf coal is deficient. The municipalities will 

 not themselves own the tramways, lighting and power com- 

 panies, but private companies will be formed to effect the 

 final distribution of the power, and the control of the price 

 charged to the consumer will rest with the municipalities 

 in virtue of their ownership of the transmission lines. The 

 -cost of carrying out the above scheme will be defrayed by 

 an issue by the Provincial Legislature cf bonds redeemable 

 at the end of forty years. 



Messrs. Townson and Mercer have submitted for our 

 inspection a technical thermometer based on a novel prin- 

 ciple. This consists of a metallic bulb containing liquid, 

 and connected by narrow copper tubing with a pressure 

 gauge. The gauge index responds to the variations in 

 pressure of the contained vapour, and this depends upon 

 the temperature of the bulb. The dial of the gauge can 

 therefore be graduated in degrees instead of pressures, and 

 is thus made into a direct-reading thermometer. The 

 Indications may, of course, be automatically recorded, as 

 in the case of an ordinary aneroid barometer. The indica- 

 tions depend only upon the temperature of the bulb ; they 

 are independent of the temperature of the gauge, which 

 may hr any distance away, the air in the capillary tubing 

 forming the connecting link which transmits the pressure 

 of the vapour in the bulb. Damage to the bulb or capillary 

 tube docs not interfere with the accuracy of the indications ; 

 NO. 2125, VOL. 84] 



the bulb and tube may, in fact, be twisted or bent in any 

 way which leaves them intact and does not prevent free 

 communication of the vapour pressure. It will be seen 

 at once that the thermometer possesses qualities which no 

 other thermometer of the same simplicity can claim, and 

 the result is that it is rapidly being adopted in works of 

 all kinds where long-distance thermometry is advantageous. 

 For e.xample, in a single cabin of a ship may be dials 

 indicating the temperature in any part of the hold, in 

 powder magazines, coal-bunkers, refrigerating chambers, 

 &c. Humidity is indicated by employing a pair, wet and 

 dry, in the ordinary way. Its use in indicating the tempera- 

 ture of superheated steam has caused it to be adopted by 

 all railways in France and by many other railways on the 

 Continent. These thermometers are made of very various 

 ranges, from —25° C. to -1-25° C, up to 450° C. to 700° C. 

 This system of temperature 'ndication is known as the 

 " Fournier " system. 



The Journal of the Franklin Institute for June contains 

 an article by E. E. Free on the phenomena of floccula- 

 tion and deflocculation, a discussion of the mechanics of 

 suspension, a subject of importance in the treatment of 

 sewage, in ore separation, and many other commercial 

 problems. The physical production of light forms the 

 subject of a paper by E. P. Hyde, and is dealt with from 

 the points of view of the laws of radiation and of physio- 

 logical optics. There are also articles on Brennan's mono- 

 rail car, the colloid nature of complex inorganic acids, 

 and the Lumi6re process of colour photogra{)hy. 



The Bulletin de la Sociiti d' Encouragement pour 

 I'Industrie nationale for May contains a paper by J. H. 

 Ricard on the pine forests of the Landes. Full details 

 are given, with numerous photographic illustrations, of the 

 methods now employed for the e.xtraction of the resin 

 (gemme), and the extraction of essence of turpentine and 

 rosin from the latter. Figures are given showing the yield 

 of pine wood per hectare, and the proportions of the wood 

 suitable for various uses. The financial aspect of the 

 industry is dealt with fully, and the great advantages of 

 the cultivation of the pine in these sandy districts pointed 

 out. 



The electrolytic conductivity of non-aqueous solutions at 

 low temperatures is the subject of a paper by P. Walden 

 in the current number of the Zeitschrift fiir physibalische 

 Chemie (June 17). Twelve organic solvents were used, 

 tetraethylammoniura iodide and tetrapropylammonium 

 iodide being used for the " normal electrolytes," the 

 observations in each case being carried down to the freez- 

 ing of the solvent. The general result of the work shows 

 that, as with aqueous solutions, the conductivity curve does 

 not cut the temperature axis with a measurable angle ; in 

 other words, there is no definite temperature of conductivity. 



The 22,000-ton floating dock lor the Brazilian Govern- 

 ment is illustrated in the Engineer for July 8. This dock 

 has been built by Messrs. Vickers, Sons and Maxim, 

 Barrow-in-Furness, at a cost of 182,700/., and is the largest 

 dock of the kind built as yet in this country. The contract 

 time for delivery at Rio Janeiro was eleven months. The 

 contract was placed on October 4 last, and the dock 

 sections were launched on June 7, 8, and 9. The designs 

 were prepared by Messrs. Clark and Standfield, of London, 

 who have already been responsible for sixty-seven floating 

 docks having an aggregate lifting capacity of 486,61)1 tons. 

 The present dock is surpassed by the 35,500-ton dock built 

 last vear by Blohm and Voss at Hamburg. Its lifting 

 capacity will also be exceeded by two box-type docks now 



