March 29, 1894] 



NA TURE 



50^ 



whistle were audible at the lighthouse when proceeding from a 

 point within the area, whilst the fog signal itself was inaudible 

 on board the steamer. This would indicate a peculiar one- 

 sided action of the boundary of the area, or a differential effect 

 upon the two kinds of sounds. Another peculiarity of these 

 areas of inaudibility is that they do not annul sounds except 

 those coming in a particular direction. Thus a vessel may be 

 in a montumbral area with respect to a fog signal. A schooner 

 with all sails set and close-hauled may be proceeding outside 

 this area in such a manner as to produce a sail-echo of the fog 

 signal audible on the first vessel. The signal will then appear 

 to those on board to come from the direction of the schooner. 

 Of the two kinds, the pseudumbral areas are the more dangerous, 

 since their place is never quite fixed, and they can only be dis- 

 covered and mapped empirically — in the present state of our 

 knowledge, at all events. 



The current number of the Electrician contains a note by 

 Prof. Fitzgerald on a recent paper of Herr P. Lenard's, which 

 appeared in Wiedeina}in's Annalen. Herr Lenard has con- 

 tinued his interesting observations on the cathode rays in gases 

 under ordinary pressures and in extreme vacua. In the experi- 

 ments with high vacua, exhaustion was carried on till a coil, 

 capable of giving a spark 15 cm. long in air, could not produce 

 any discharge between terminals sealed into the experimental 

 tube. Herr Lenard estimates that, when he had condensed 

 the mercury vapour in a connected globe by lowering its 

 temperature to -21° C, the pressure of the remaining gas was 

 about 0*03 X lo"" of an atmosphere, or about 0'03 dyne per 

 square centimetre. In a tube in which the exhaustion had been 

 carried to this extent nothing was visible on the path of the 

 rays except where they impinged on the glass at the opposite end 

 of a tube 150 cm. long, and when there were no magnets near, 

 they were propagated in straight lines. From these and many 

 other interesting observations Herr Lenard concludes that the 

 cathode rays are phenomena in the ether, and are independent 

 of the presence of matter. With reference to this point Prof. 

 Fitzgerald says : — "If this be so they are a most remarkable 

 addition to the properties of the ether. Phenomena that may 

 all be classed under light propagation are the only known 

 phenomena of propagation in free ether. There is a very 

 essential difference between these cathode rays and ordinary 

 light propagation, and only for this these rays might be very 

 rapid ultra-violet waves, which are known to be rapidly ab- 

 sorbed by air and other gases, but which may be able to run 

 the gauntlet of hundreds of thousands of molecules without 

 being finally absorbed, and might, in accordance with the 

 known transparency of gold leaf, be able to penetrate any solid, 

 even though a conductor, because for their extremely rapid 

 vibrations the molecular motions upon which ordinary con- 

 ductivity depends may be much too slow to have any sensible 

 effect. The fact that seems conclusive against this view is the 

 deflection of the rays by a magnet. These rays are deflected 

 in the same way as a conductor carrying a current of electricity 

 away from the cathode. No such action has ever been ob- 

 served on rays of light. It would be most natural to explain 

 the action by the presence of the matter which is generally 

 required in order to be acted upon by a magnet. There seems 

 very little reason for supposing that a magnet would act upon 

 electric displacement currents in the ether, even if displacement 

 currents of the straight ray kind were possible in the ether with- 

 out propagating themselves out sideways with the velocity of 

 light. When we recollect that in the vacua described by Herr 

 Lenard there are still lo^** molecules par cubic m.m. there does 

 not seem sufficient reason for looking to an unknown property 

 of the ether when there is so much matter present to explain 

 the phenomenon." 



NO. 1274, VOL. 49] 



Prof. Kayser and Runge's seventh paper on the spectra of 

 the elements, communicated to the Berlin Academy of Sciences 

 in December last, has been published in separate form. The 

 elements of which the spectra are described in the paper are 

 tin, lead, arsenic, antimony, and bismuth. In the case of the 

 spectrum of tin the lines extend from wave-length 2053 8 to 

 5631 '91, and fourteen lines are marked as new. The spectrum 

 of lead was investigated between A\ 20885 ^'^^ 600208, and 

 thirteen new lines were discovered. Lines are tabulated for 

 arsenic from A2009"3i to A 3ii9'69. The antimony spectrum 

 is limited by a line at 2068 "54 in the ultra-violet, and one at 

 5730'52 rn the red, seven new lines being included. Bismuth 

 has had its spectrum observed between the wave-lengths 

 2061 77 and 574274, and twenty-two new lines have been dis- 

 covered. At the end of the paper the authors discuss the 

 distribution of the lines and groups in the different spectra, 

 and show that the positions admit of being determined 

 mathematically. 



The behaviour of the filtrate from tetanus cultures when ex- 

 posed to sunshine is perhaps the most interesting of the nume- 

 ous observations made by Fermi and Pernossi. Already in 

 1891 Kitasato tested the pathogenic properties of tetanus filtrates 

 obtained from broth cultures kept in the dark and light respec- 

 tively, and found that exposure to diffused light gradually ren- 

 dered them innocuous; it was, however, a very slow process, for 

 even after from nine to ten weeks the filtrate was still feebly 

 toxic. On the other hand, similar filtrates preserved in the dark 

 were still, after 300 days, just as actively pathogenic to animals 

 as when they were originally prepared. In direct sunshine 

 (35°-43° C), however, such filtrates were rendered perfectly 

 harmless in from fifteen to eighteen hours. On the other hand, 

 Fermi and Pernossi found that the toxic properties were de- 

 stroyed after from eight to ten hours of sunshine during which 

 the maximum temperature reached was between 38°-4i° C. , 

 whilst when similarly exposed, the temperature, however 

 (owing to the experimental tubes being immersed in water), not 

 rising beyond 37° C. it required fifteen hours to produce the 

 same result. When, however, the filtrate was first dried and 

 then exposed to sunshine, it remained toxic even after io3 

 hours' insolation, the same results being obtained when the de- 

 siccated filtrate was mixed with chloroform, ether, benzol, and 

 amyl alcohol respectively, and exposed to sunshine. The 

 elaborate nature of the experiments, as well as the large number 

 undertaken and the conscientious care with which they have been 

 conducted, combine to render this one of the most important 

 memoirs which has been yet published on the subject of tetanus. 



A further illustration of the singular media in which fungi 

 will thrive is afforded by the observation of M. Heim, recorded 

 in the Bulletin of the Societc Mycologique de France, of an 

 abundant fungus-mycele in a solution of sulphate of quinine. 

 It produces a fructification which shows that it belongs to the 

 genus Aspergillus, and M. Heim proposes for it the name 

 Aspergillus quinina sp. n. (?). 



The annual report of the Board of Regents of the Smith- 

 sonian Institution, showing the operations, expenditures, and 

 condition of the institution to July 1891, has just reached us. 

 The volume contains an appendix comprising a selection of mis- 

 cellaneous memoirs of interest to collaborators and correspon- 

 dents of the institution, teachers, and others engaged in the 

 promotion of knowledge. 



We have received parts i. and ii. of the thirty-seventh volume 

 of the Transactions of the Royal Society of Edinburgh, and 

 vol. XX. (pp. 97-160) of the Proceedings. Among the investi- 

 gations described in the volumes we note the work of Prof. 

 Crum Brown and Dr. James on the electrolytic synthesis of 



