952 



NA TURE 



[Df 



water, prohibit the existence nf diiierent herring races 

 in the North Sea. 



EUCALYI'TUS On s AS i 



Penfold and K. Grant givt 

 tion of the gerniicida! ••» 

 Walker carboUc acid 

 coniniercial eucalyptu 



nga- 



,,....<>. ...^ ivuleal- 



of the principal 



ii their active con- 



stituents (Journ. and I'roc. Koy. S<x;. of N.S. Wales, 

 vol. Ivii,, 1923, p. 80). Standard suspensions of 

 t per cent, of the crude oils and their pure constituents 

 were made in 74 per cent, resin soap solution. Of 

 the oils of ten species of Eucalyptus, that of E. radiaia 

 was the strongest and gave a cocflicient of 10-12, 

 the active principle being piperitol. Of active 

 principles, australol, geraniol, citral, and piperitol 

 gave coefficients of 22-5, 21, 19*5, and 13 respectively. 

 The interesting observation is made that a lower 

 coefficient is gfiven by the dilution (with water) of a 

 concentrated preparation than by a dilute prepara- 

 tion of the same strength, probably because the 

 dilution of a concentrated emulsion upsets the 

 emulsion. 



Red Discoloration on Dried Salted Fish. — 

 The condition known as " pink " is one to which 

 dried salted fish is liable, and is characterised by the 

 appearance of pink patches on the surface. It is 

 dealt with in Special Report No. 18 of the Food In- 

 vestigation Board by Dr. P. C. Cloake. These pink 

 patches are caused by the growth of chromogenic 

 micro-organisms of at least two species — one a red 

 sarcina, the other a curiously polymorphic form 

 which may be a bacillus. These organisms may be 

 cultivated on such media as salted fish agar, provided 

 they contain a high percentage of salt, e.g. 15 per 

 cent., at a temperature of 24° C. The source of 

 these organisms has been traced to the salt used in 

 curing when this is of marine origin ; rock salt 

 seems to be free from them. Sterilisation of the 

 salt at 120° C. for 30 minutes suffices to destroy the 

 organisms. 



A Suggested Indicator for Petroleum. — In 

 the Journal of the Royal Society of Western Australia, 

 vol. 9, p. 8 (1923), A. Farquharson describes an occur- 

 rence of the hydrocarbon impsonite, infilling the 

 vesicles of a basalt that underlies a limestone variously 

 regarded as of Cambrian or Lower Carboniferous age. 

 Specimens have been collected from various points in 

 the Ord Valley near Kimberley, West Australia, and 

 these were sent to the office of the Geological Survey 

 in the first instance as possibly oil-bearing shales. 

 The author points out that the occurrence is of 

 sufficient magnitude to have a bearing on the search 

 for petroleum in the district. We need not share his 

 view (p. 17) that oil would be unlikely to occur if the 

 rocks were of Cambrian age, since seepage from a 

 distance is always possible, and the highly vesicular 

 character of the basalt may have provided a favour- 

 able storehouse on the way. As E. H. Cunningham 

 Craig remarks, migrating petroleum will make its 

 appearance in " the most porous rock available." 



Climatic Changes and Weather Normals. — 

 The U.S. Monthly Weather Review for August contains 

 an article by Prof. C. F. Mar\an. Chief of the U.S. 

 Weather Bureau, on the above subject. The dis- 

 cussion is introduced by a question, " Is the climate 

 changing ? " and justifies the answer of " Yes " or 

 " No " to this inquiry. Geological records are said 

 to leave no question as to the great changes the vast 

 lapse of time has occasioned in the past, while there 

 is said to be no conclusive evidence of notable 



NO. 2826, VOL. I 12] 



permanent changes during thousands of yean 

 nunuin history. The author believes that long>tti 

 fluctuations of cUmatic conditions have occurred. 

 and that minor surgings of the seasons to and fro 

 take place for such periods as 50 to 100 years. 

 Reference is made to the somewhat gener-' '•'•'•^>- 

 scated conviction that, to many, weather • 

 at the present time differ from rorrr'^ixn 

 ditions within their memory. Ti 

 the discu.ssion is to establish a mt-; 

 a broken record of observations, say of tt-: 

 or rainfall, so as to lengthen out to the 

 series of observations and thus to secure loii- |.. ii-i 

 normals of obser\'ations to aid in obtaining j-i • i "f 

 secular changes if such are obtainable. A nn'h'"l 

 is suggested for completing the individual valms 

 for missing years wliich is practically a system of 

 drawing lots from the values of all the years for 

 which observations exist, and so on for all the ' 

 for which means are required. This system sea 

 seems likely to commend itself to all workers, 

 siderable importance is attached by the author i 

 use of accumulated sums of departures from a n^ 

 base and exhibiting the same as a graph. 



Photoelectric Cells for Measurements 01 

 Time. — In the Comptes rendus of the Paris Academy 

 of Sciences. November 5, 1923. Messrs. G. Ferrie, K 

 Jouart, and K. Mesny describe methods employed to 

 amplify the current from a photoelectric cell, so that 

 the amplified current can be used to record the passa«< 

 of a pendulum through a certain point of its patli 

 The anode of the photoelectric cell was joined to th<- 

 grid of a special triode valve, and the filament of th( 

 valve to the positive of a battery', the negative ot 

 which was connected to the deposit of alkali metal 

 in the cell ; a constant high potential difference wa^ 

 applied between the anode plate and the filament of 

 the valve. When the cell was illuminated, the grid 

 was charged negatively, and the current of the valve 

 was diminished. In this way a variation of current, 

 10,000 times as great as the original photoelectric 

 current, can be obtained ; and, by attaching to a 

 pendulum a screen, provided with a slit, thronfdi 

 which light from an electric lamp can pass, me 

 ments of the time of vibration can be made witli 

 siderable accuracy. With a more complicated arrange- 

 ment of valves, an amplification of the order lo* was 

 obtained and it wcis possible to determine the perio<l 

 of the pendulum within one-thousandth of a second. 

 The authors hope to be able to adapt the method for 

 recording the passage of stars across the central line 

 of a meridian telescope. 



Velocity Distribution of Electrons from In- 

 candescent Oxides. — The velocity distribution of 

 the electrons ejected from incandescent substances 

 has been investigated by the integral method, not 

 attempting to separate out the electrons moving at 

 or near a definite velocity, but deducing the distri- 

 bution law from observations which included all the 

 different velocities present ; Richardson used also 

 the differential method. All the observers have 

 found that Maxwell's probability^ law for the distribu- 

 tion of the velocities is correct in the case only of 

 clean metal surfaces. In the Zeitschrift fur Physik. 

 November 15, 1923, HerrM. Rossiger describes experi- 

 ments, using the differential method, in wliich the 

 electrons pass through a longitudinal slit, parallel to 

 the axis of the cylindrical anode ; this is coaxial with 

 a straight, incandescent platinum wire which forms 

 the cathode and is coated with oxides of calcium, 

 barium, or strontium. There is an outer cylinder, 

 coaxial with the first, and electrically connected with 



