:8o 



NATURE 



[June 12, 1913 



"Forecasting the weather" is the title of an in- 

 teresting bulletin (No. 42) by Mr. G. S. Bliss (section 

 director), recently issued by the U.S. Weather Bureau. 

 It shows the great advantage enjoyed by the bureau 

 in being able to watch the developments and move- 

 ments of storm-areas over the entire country between 

 the Atlantic and the Pacific, and from Canada to 

 Mexico and the West Indies, by the receipt of tele- 

 grams twice daily containing observations made at 

 the same physical instant of time. The author shows 

 how perfectly the machinery works, and how rapidly 

 the operations are performed, from observation to 

 map-making. In less than two hours the various 

 forecasters are prepared to issue particulars for a 

 day or two in advance for any State or city with nearly 

 as high a degree of accuracy as they can for their own 

 locality. This useful bulletin is accompanied by 

 weather maps and an epitome of the various pro- 

 cesses at work in the atmosphere, to assist students 

 in applying to the maps the principles learned in a 

 cursory study of the elements. It is claimed that by 

 mapping the whole northern hemisphere the Weather 

 Bureau is enabled to forecast general conditions for 

 a week or ten days in advance with a creditable 

 degree of accuracy. 



It is well known that the distance of the epicentre 

 of a great earthquake is determined by the duration 

 of the first series of preliminary tremors. The rela- 

 tion is not a simple one for all distances, but Mr. 

 G. Negri states (Anales de la Soc. Cien. Argentina, 

 vol. lxxv., 1913) that the duration I, of the pre- 

 liminary tremors in minutes and the distance S of 

 the epicentre measured along a great circle in 

 thousands of kilometres are connected by the follow- 

 ing relations : if S be equal to or less than 1, I, = 2-o5.S, 

 if S lie between 1 and 9, I,= ^(16834.8) — 2-32, and if 

 S be greater than 9, I, = (8 + 5-929)/ 1-463. Thus the 

 curve which represents these relations consists of 

 three portions which are respectively straight, para- 

 bolic, and straight. Mr. Negri suggests that earth- 

 quakes which originate at distances represented by 

 the above limits might be termed near, distant, and 

 antipodal. 



In the May number of The American Journal of 

 Science, Prof. L. P. Wheeler, of Yale, examines the 

 more recent measurements of the refraction and dis- 

 persion of metals in the light of the electron theory 

 of dispersion. The experimental data cover silver, 

 copper, gold, nickel, and cobalt, but the accuracy 

 attained is still insufficient to make the comparison 

 satisfactory. It appears, however, from the results 

 available that the number of free electrons in each 

 of these metals must increase with the frequency of 

 the incident radiation slowly and fairly uniformly in 

 the infra red, and more rapidly in the regions for 

 which the metals are transparent. The dispersion due 

 to the free electrons is more important than that due 

 to the bound electrons, especially in the region of 

 short wave-lengths, and the form of the dispersion 

 curve given by theory agrees with that found experi- 

 mentally in its main features, although the inaccuracies 

 of the experimental results do not permit of any 

 satisfactory comparison of details. 

 NO. 2276, VOL. 91] 



Science Progress for April contains an important 

 article by Dr. J. V. Eyre on the projected revival of 

 the flax industry in England. Dr. Eyre has, on 

 behalf of the Development Commissioners, visited, 

 during the past two years, the principal flax-growing 

 countries of Europe, and made a special study of the 

 methods adopted in cultivating the plant and separat- 

 ing the fibre. The information gathered has been 

 recently presented to the Commissioners in the form 

 of a report, which is summarised in the article now 

 referred to. The inquiry leaves no room for doubt 

 that the climate of this country is well suited to flax, 

 and experiments are in progress as to the possibility 

 of cultivating and separating the fibre at a profit. 

 Taking into account the fact that flax is now worth 

 nearlv twice as much as it was ten years ago, and 

 other considerations which are specified in detail, there 

 is strong reason to believe that the judicious revival 

 of the industry by improved methods would be of 

 benefit to British agriculture. During the past year 

 flax was grown in Bedfordshire experimentally as a 

 fibre crop, and useful information gained as to the 

 more difficult operations of harvesting and retting, 

 special tanks being constructed for the latter purpose. 

 It is proposed in the present year to make trials on 

 a larger scale, and for this purpose a society has been 

 formed under conditions of non-profit trading, so as 

 to be eligible for a grant from the Development Com- 

 mission. 



The third of a series of articles on the Panama 

 Canal appears in Engineering for June 6, and deals 

 with the lock-gates. The locks are 1 10 ft. wide, and 

 have a nominal length of 1000 ft. ; intermediate gates 

 are provided, together with valves, allowing lengths 

 of chamber of 2785, 370, 55°. 908-5 and 1000 ft. re- 

 spectively to be employed, an arrangement which will 

 result in a considerable saving of time and water with 

 vessels of short length. The gate leaves are built 

 of fiat girder work sheathed with plating, and the 

 whole of the support is given by a pintle at the base 

 and a yoke above; there is no roller path provided. 

 The leaves have a length of nearly 65 ft. and are 

 7 ft. wide ; the largest are 82 ft. high. The largest 

 leaf has a weight of 1,483,700 lb. The material used 

 in the gates is open-hearth steel, having an ultimate 

 tensile strength of 60,000 lb. per sq. in. Under 

 ordinary conditions, the working stresses do not exceed 

 13,000 lb. per sq. in., and do not excued 15,000 lb. 

 per sq. in. under extreme conditions. 



The city of Edinburgh recently appointed a com- 

 mission " to visit various cities in England with a 

 view of inspecting self-propelled cars and obtaining 

 further information on the subject." The deputation 

 has issued a report which is commented upon in 

 Engineering for June 6, and gives some valuable data 

 as to various installations for running tramcars by 

 petrol, in place of by cable or b}' electricity. At More- 

 cambe the autocar service was opened eighteen months 

 ago : the line is 1-2 miles long, and passes through 

 a sparsely populated district. The first year's work- 

 ing shows a surplus of receipts over all expenditure. 

 The car seats thirty-seven passengers; its weight un- 

 loaded is 8 ton-.. It is propelled by a 40 h.p. four- 



