EPTEMBER 3, I914] 



NATURE 



I\ It is satisfactory to note some improvement in 

 rate of transmission of wireless reports ; a wireless 

 eiving apparatus has been installed at the office for 

 -ages forwarded from the Eiffel Tower. Com- 

 mons of the weather forecasts and storm warning 

 :^rrams for the United Kingdom with subsequent 

 iher show that the percentage successes have been 

 satisfactory. As an appendix to Dr. Shaw's 

 esting report is reprinted a circular containing 

 il particulars relating to the international units 

 easurement recently adopted 



ME interesting notes on the changes occurring 



ig the manufacture of tea are given in a paper by 



S. Sawamura in tjie Bulletin of the Imperial 



ral .Agricultural Experiment Station of Japan. In 



manufacture of green tea the oxidising enzymes 



le leaf are killed by steaming, but it is essential 



the steaming should not be too far prolonged, 



rwise other enzymes, which play a part in the 



roduction of the aroma, are also destroyed, and the 



.ihsequent quality is impaired. The effect of rolling 



leaves is to increase the easy solubility of the 



jii^tituents which give quality to the infusion, and 



tthe same time desiccation of the leaves is also 

 celerated owing to juice being pressed out from the 

 iterior of the cells. Experiments are also described 

 howing the effect of different temperatures during the 

 firing " of the leaves. 



.\n interesting contribution to the study of the 

 ormation of hydrogen cyanide in plants is contained in 

 paper by Prof. A. Jorissen in the Bulletin of the 

 oyal Academy of Belgium (1914, p. 130). It is 

 hown that citric acid in presence of oxidising agents 

 Imd a trace of a nitrite gives rise to hydrogen cyanide, 

 probably owing to the action of the nitrite on acetone- 

 picarboxylic acid, which is the first product of the 

 t)xidation. In dilute solution and in sunlight it is 

 phown that small quantities of ferrous or ferric salts 

 pan effect the preliminary oxidation of the citric acid, 

 jeven ferrous bicarbonate being sufficient for the pur- 

 pose. Citric acid is widely diffused in plants, and 

 {light, which brings about its o.xidation in presence of 

 jtraces of iron, is also well known to favour cyano- 

 Igenesis. It is probable therefore that the above de- 

 scribed synthesis of hydrogen cyanide is one which is 

 realised in the actual plant in many instances. 



The success of the" Tee " process for the produc- 

 tion of white salt from rock-salt gives occasion for 

 an illustrated article in Engineering for August 21, 

 descriptive of the works now in operation at Carrick- 

 fergus, in Ireland. In this process the rock-salt is 

 fed into a gas-fired furnace, where it melts and runs 

 from the furnace into a "bath." The bath contains 

 a slagging chamber, on the floor of which the greater 

 proportion of the impurities is deposited; the molten 

 ^alt then reaches other two chambers in the bath, 

 each containing a 3 in. wrought iron pipe with a 

 number of i in. holes through which compressed air 

 at a pressure of from 8 to 10 lb. per sq. in. is blown. 

 The state of agitation into which this throws the 

 molten salt results in a further deposit of slag in both 

 <:hambers. The molten salt then passes slowly through 

 -\0. 2340, VOL. 94] 



a settling-chamber, thence to a reservoir, and finally 

 through two tap-holes to the rotary pans. The rotary 

 pans crystallise the molten salt in one operation by 

 means of stationary rakes, the latter performing the 

 function of agitating the rapidly-cooling molten salt 

 in such a manner as to crystallise it, ready for the 

 market, in various grades, and sized according to 

 requirements. The total rated capacity of the three 

 furnaces at Carrickfergus is 70 tons of refined salt 

 in 24 hours. The whole operation is continuous, the 

 salt being deposited in a finished state ready for the 

 market within half-an-hour of coming out of the 

 mine. 



The Cambridge University Press has added two 

 further volumes to its series of Cambridge County 

 Geographies, which when complete will cover the 

 whole of the British Isles. One volume is on 

 Glamorganshire, and is written by Mr. J. H, Wade; 

 the other deals with Durham, and is by Mr. W. J. 

 Weston. As in other cases, the books are brightly 

 written, and give a readable account of the geography 

 and geology of the areas, followed by a description 

 of their economic resources and history. The maps, 

 illustrations, and diagrams will maintain the high 

 standard reached in previous volumes. 



OUR ASTRONOMICAL COLUMN. 



The Recent Perseid Shower of Meteors. — Mr. 

 Denning reports that many observations from various 

 stations have come to hand, and that the results are 

 of a singularly interesting character. Though the 

 shower was rather noteworthy for its brilliant meteors 

 '. it was not exceptional as regards numbers. The fine 

 j weather which prevailed afforded some recompense for 

 the moonlight. More than thirty bright meteors were 

 observed at two stations or more, and their heights, 

 radiants, and velocities have been found. The maxi- 

 mum occurred on August 11, but there were a few 

 belated Perseids as late as August 20. One feature 

 of the recent shower was that a number of fine 

 meteors were not Perseids, but members of one or 

 other of the many minor radiants which abound at 

 this time of the year. The most conspicuous of these 

 was in Lvra at 280° + 44°, and there were others at 

 292° + 5i°; 3i2° + 6i°, 354°+77°, 309° + 6°, and 

 74° + 33°- 



The last three showers were seen during the latter 

 part of the month. The Aquilids at 309°+ 6^ appear 

 to form a new display, which, if it has been previously 

 visible, seems to have eluded detection. The meteors 

 are bright and move slowly in rather long flights. 

 The display in Auriga at 74° + 33° forms a pretty active 

 display of swift conspicuous meteors leaving bright 

 streaks. This shower was also seen on the morning 

 of August 28, 1881, by Mr. Denning. He describes 

 the meteors as being of ver\' great velocity, and often 

 having very extended flights across the firmament. A 

 brilliant member of the stream was recorded on 

 August 28 last at loh. 25m. p.m., moving along a 

 path of 84° from a few degrees N. of a Arietis, almost 

 to the planet Jupiter. It was also seen from Kent, 

 where its path was estimated as 100° long. It passed 

 from over Kent to the English Channel about seventv- 

 five miles S. of Portland Bill. Path, 182 miles, arid 

 velocity forty-five miles a second. 



CcMET 1913/ (Del-w.^k). — ^The accompanying chart 

 is intended for the use of those who desire an easy 

 means of finding Delavan's comet, which is now a 



