574 



NATURE 



[January 20, 19 16 



wherever grown, irrespective of soil and climate, in 

 about the same proportion as iron. If Mr. Headden's 

 view is correct, the discovery opens up a new field 

 of research in order to determine the physiological 

 function of manganese in vegetable metabolism. 



An account of an exceptionally heavy rainfall during 

 a thunderstorm at Malta has been received from 

 Dr. Thos. Algius, the officer in charge of the meteoro- 

 logical observatory attached to the university. The 

 thunderstorm passed over the island during the early 

 hours of November 22 of last year, and the amount of 

 rain registered is said to be nearly equal to that known 

 as the St. Nicholas day outburst some forty years ago. 

 The barometer fell nearly two-tenths of an inch prior 

 to the downpour, and the direction of the wind was 

 south-easterly, increasing in velocity to 25 miles an 

 hour and to nearly 30 miles an hour in gusts. The 

 air temperature dropped suddenly from 65° to 58°. 

 The rainfall registered at the observatory was 7*24 in., 

 but ii'57 in. fell during the cloudburst on October 16, 

 19 13. Rainfall returns supplied by the elementary 

 schools well scattered over the Maltese islands have 

 provided data for mapping the fall, which ranged from 

 8'6o in. to a much more modest measurement. 



The mean salinity and surface temperature of the 

 North Atlantic and English Channel for June, July, 

 and August, 19 15, are shown in a series of charts on 

 the Monthly Meteorological Chart of the North Atlan- 

 tic for January, 1916. Charts are also given showing 

 the average salinity and surface temperatures of the 

 English Channel for the same months during the last 

 eleven years. The charts were prepared by Dr. E. C. 

 Jee, from British and Dutch data. They all show a 

 persistent decrease in salinity from the mouth of the 

 Channel eastward to the Straits of Dover, but they 

 show no marked deviation among the three months. 

 In addition to the usual features of the monthly issue, 

 the January number contains also a table giving the 

 percentage of days with fog at lighthouses on the 

 Newfoundland coast, in most months for an average 

 of ten years. 



The papers on the heating of electric wires and 

 cables by Messrs. Melsom and Booth, which are re- 

 produced in vol. xii. of the Collected Researches of 

 the National Physical Laboratory, form the starting- 

 point of an investigation of great importance in elec- 

 trical engineering. So little is known about the heat 

 conductivity of materials in which cables are enclosed 

 when in use that the views held by different authorities 

 as to the greatest currents they will safely transmit 

 are widely divergent The National Physical Labora- 

 tory is obviously the authority to whom a difficult 

 subject of this kmd should be referred, and electrical 

 engineers will look forward with confidence to the 

 publication of further reports. 



Palm-oil, which is used in very large quantities in 

 the soap industry, is bleached (i) by exposure in thin 

 layers to air and sunlight ; (2) by blowing air through 

 the hot oil ; (3) by the action of bleaching-powder, or 

 chromic acid. The very great development in this 

 country and elsewhere of catalytic reduction, as a 

 means of hardening fats and oils, appears to have sug- 

 NO. 2412, VOL. 96] 



gested the desirability of applying similar methods to 

 the oxidation and bleaching of the oils. The experi- 

 ments of Mr. S. G. Sastry (Trans. Chem. Soc, 107, 

 1828) showed that a large number of metallic com- 

 pounds could be used to stimulate the oxidation, the 

 most effective being those containing manganese and 

 cobalt, although nickel, iron, and lead were also active. 

 Of the various compounds employed the borates were 

 found to be more efficient than the oxalates, palmitates, 

 sulphates, or oxides, and the most efficient of a dozen 

 catalysts was cobalt borate. Using only 001 per cent, 

 of this salt, a reddish sample of oil was bleached white 

 in the course of 35 hours by passing air through it at 

 80° to 90° C. The bleaching was found to be per- 

 manent during fifteen months, and did not destroy the 

 faint odour of violets which is characteristic of the 

 oil ; the bleached oil also gave a colourless soap, and 

 its soap-making qualities were not interfered with in 

 any way. 



An account of a research on stable biplane arrange- 

 ments, conducted at the wind tunnel of the Massa- 

 chusetts Institute of Technology, is given in Engineer- 

 ing for January 7 and 14. The author is Mr. J. C. 

 Hunsaker, assistant naval constructor in the United 

 States Navy. The object of the research was to dis- 

 cover whether the longitudinal instabihty of the typical 

 cambered aeroplane wing may be overcome without 

 material sacrifice of lift, or increase in resistance. 

 It is believed that the experiments show that the 

 ordinary biplane, using wings of standard section, 

 may be made longitudinally stable by giving the 

 upper plane a stagger forward of 50 per cent, of the 

 chord, and at the same time inclining its chord about 

 2^° to the lower chord, "decalage" 2|°. The loss 

 in maximum lift to drift ratio ("efficiency") is less 

 than 5 per cent. The maximum possible lift is not 

 diminished, but increased slightly, and the landing 

 speed of the aeroplane is thus the same whether this 

 arrangement or the ordinary one be used. Further, 

 the maximum speed is identical in both cases. In 

 practice, the unstable pitching moments of ordinary 

 biplane wings are balanced by a large horizontal tail 

 surface. The increased structural weight due to 

 inclined struts in a staggered biplane should be com- 

 pensated, at least in large part, by the saving in 

 weight due to a smaller tail surface and lighter sup- 

 porting stru:ture. 



Engineering for December 31 contains a paper on 

 recent progress with the active type of gyro-stabiliser 

 for ships, read by Mr. Elmer A. Sperry at the Society 

 of Naval Architects and Marine Engineers, in New 

 York, on November 19 last. The paper describes the 

 first commercial gyroscope-stabilising equipment to be 

 installed, which was fitted on the yacht Widgeon, 

 owned by Mr. H. M. Hauna, jun., of Cleveland. This 

 was placed in service in the autumn of 1915. The 

 system of control is practically identical with that 

 adopted in former experiments on the Warden ; a small 

 auxiliary gyro feels out the incipient rolling of the 

 ship by closing electrical contacts, and, through a 

 relay switch, actuates a small reversing motor, which 

 is geared to the case of the stabilising gyroscope and 

 causes it to precess in its bearings. The stabilising 



