May 30, 19 1 8] 



NATURE 



25 



The report on rainfall registration in 1916 in Mysore 

 has just roached us. It includes maps showing the 

 actual rainfall for the year 1916, and the average 

 annual rainfall for the period 1870-1915. On June 25, 

 i()i6, more than 16 in. of rain fell during twenty-four 

 hours at Nagar in the Shimoga district ; the total 

 rainfall at that place during June was 38 in., nearly 

 so per cent, above the normal, although the total fall 

 tor 1916 was practically normal at 104 in. The rains 

 during October and November, 1916, were above the 

 normal on account of an exceptional number of cyclonic 

 storms, which originated in the Bay of Bengal. The 

 rains were on the whole but half of the normal during 

 the cool-weather period, January and February, and 

 ^ilso during March, the beginning of the hot-weather 

 period. The deficiency was more than made up during 

 the rest of the year, especially in the north-east mon- 

 soon period from October to the end of the year. The 

 tables occupy fifty-eight pages, and give the details 

 for the 224 stations under various heads ; a notable 

 table is that which gives the distribution in the river 

 valleys. 



Weather-controls over the fighting in Meso- 

 potamia, in Palestine, and near the Suez Canal is the 

 subject of an article by Prof. Robert DeC. Ward, of 

 Harvard University, in the Scientific Monthly (April). 

 Mesopotamia is characterised as " a country of aridity, 

 of intense summer-heat, of deserts and steppes, of 

 relatively mild winter, and of cold-season rains." The 

 mean temperature at Bagdad for January is given as 

 487° F., and for August 92-5°; the mean maximum 

 is 119-5°, ^"<i ^he mean minimum 219°, which are the 

 mean extremes in the year. Winter frosts occur and 

 snow falls locally. The total mean annual rainfall 

 is only about 8 in. or 9 in., and in some years only 

 about half as much. The rain falls between October 

 and May, and the remaining months are practically 

 rainless. February or March is the rainiest month, 

 and the floods come in March and April. The climate 

 of Palestine has been discussed by Exner and Hann, 

 and the article quotes various data. The coast stations 

 have a mean midwinter temperature of between 50^ 

 and 55° F., and mean midsummer temperature of 75° 

 to 80°. The hill stations, at elevations of about 

 1500 ft. to 3000 ft., have mean midwinter tempera- 

 tures from 45° to 50°, and midsummer means from 

 70° to a little under 80°. In the Jordan valley the 

 temperatures range from 55° in midwinter to 85° or 

 90° in midsummer. Jerusalem averages 3-6 days a 

 year with temperature below freezing, and the highest 

 summer temperatures reach 100° to 105°. The annual 

 rainfall at the coast stations ranges from 15 in. to 

 35 in., and at Jerusalem it is 26 in., no rain falling 

 in June, July, and August. The rainy season extends 

 from the middle of October to early in May. In the 

 district of the Suez Canal the complete absence of 

 rain for months together and the exceptionally small 

 total annual fall in places immensely augments the 

 difficulty of transport. The writei" of the article says 

 th^t winter is the best season for a campaign, both on 

 account of the better water supply and of the lower 

 temperature. 



A PRELIMINARY report on the mineral production of 

 Canada during the year 19 17 has been issued by the 

 Canadian Department of Mines. Although the total 

 value of this production shows an increase over that 

 for the previous year to the extent of 8*9 per cent,, 

 this is due almost entirely to increased values of the 

 products, the quantities showing actual decreases in 

 many cases. Thus the coal output, a little above 14 mil- 

 lion tons, shows a decrease of 3*2 per cent. ; the pro- 

 duction of copper shows a decrease of 7*08 per cent., 

 of lead of 22*71 per cent., of silver of 13 per cent., 



NO. 2535, VOL. lOl] 



and of gold of 19-68 per cent. On the other hand, the 

 production of zinc increased by 33*5 per cent., and 

 that of cobalt by 29-62 f>er cent. There were trifling 

 increases in the production of nickel and of pig-iron, 

 though in the latter case this was due entirely to the 

 I production of iron in the electric furnace; further- 

 1 more, the pig-iron produced from Canadian ores 

 I showed a heavy decline, more imported ore havjng 

 been smelted in 1917 than in 1916; a large projjortion 

 of the latter consists of Wabana ore from Newfound- 

 land. Upon the whole, it may fairly be said that the 

 mineral industry of Canada is holding its own reason- 

 ably well under the severe stress of war conditions. 



In the Elekttotechnische Rundschau for Septem- 

 ber 26, 1 9 17, a writer directs special attention to the 

 process of steel hardening by air-blast, owing to 

 shortage of oils in Germany. The hot tool is placed 

 in an attachment capable of rotating freely. It is 

 then exposed to the cold blast forced through a number 

 of tubes in such a way as to rotate the tool. Drills, 

 turning-tools, and other simple pieces may be cooled 

 in the blast from a fan. 



Acceleration in the deposition of metallic deposits 



may be obtained by suitable electrolytes, stirring the 



bath, and applying high temperatures. In this way 



it has been possible (according to Elektrotechnik und 



Maschinenbau, October 14, 19 17) to produce cobalt 



deposits in three to five minutes with a current density 



of 29 amps, per dm.^ A nickel deposit that previously 



required I2 hours can now be made in five minutes 



I by using a solution of 220 grams nickel-sulphate, 



I 21 grams nickel-chloride, and 21 grams boracic acid 



to one litre of water at 70° C, and using a current 



density of fr«m 25 to 39 amps, per sq. dm. The 



! action of high temperatures is said to bring about an 



j increase of concentration of the ions. The method 



; is not of universal application, as all solutions do not 



j allow high temperatures to be used. 



K. H. Guldner, in the Zeitschrift des Vereines 

 deutscher Ingenieure for .\ugust 11 and i^, 19 17, 

 describes some investigations which he has carried out 

 to determine the lateral deviation of projectiles caused 

 by the spin imparted to them by the rifling of a 

 trench-mortar. The trench-mortar provides a suitable 

 means of carrying out such tests, as the motion of 

 the projectile may be followed by the eye. Rifling 

 with a right-handed twist may cause constant lateral 

 deviation both to the right and left. Right or left 

 deviation is the result of right or left precession, and 

 is visible to the naked eye. Left precession u-ith 

 rifling having a right-handed twist can occur only 

 after the maximum height of the trajectory has been 

 passed if the centre of action of the air-resistance 

 lies behind the centre of gravity of the shell. The 

 precession on the ascending part of the trajectory is 

 always greater than in the descending part. 



The making of accurate screw gauges presents con- 

 siderable difficulties, as is well known to those who 

 undertook to manufacture these appliances for the 

 Ministry of Munitions. \ lathe having many novel 

 : features has been designed and made at the request of 

 I the Ministry by Messrs. Bryant, Symons, and Co.. 

 j 320 St. John Street, London, t.C.i, and is described 

 j in Engineering for May 24. Both centres are dead 

 centres, thus ensuring that work shall be round and 

 not slightly elliptical. The efTective pitch of the lead 

 screw can be varied at will, so that it can produce a 

 thread of slightly greater or smaller pitch than the 

 standard; in this way shrinkage during hardening can 

 be provided for in advance. The lead screws of all 

 these lathes are tested' separately, and a correction bar 



