May i6, 1895] 



NATURE 



00 



■ .n this subject by no means exhaust it ; Ijui I think it may be 

 safely asserted that selection has yielded much more than sports. 



W. BOTTI.NG HeMSLEY. 



TERRESTRIAL HEUCM. 



Prof. Milne's Observation of the Argentine Earth- 

 quake, October 27, 1894. 



A FEW days ago I received from Prof. Milne a letter, dated 

 March 15, 1895, in which he sends me a list of earthquake dis- 

 turbances, compiled from the records he was fortunate enough to 

 rescue from the fire which destroyed his house on P^ebruar}' 17. 

 In this list I find no less than three obser\'ations of the great ' 

 Argentine earthquake of October 27, 1894, which was recorded 

 by three different horizontal pendulums. The times given for 

 the beginning of the earthquake — viz. iSh.iom., i8h. 5m., I7h. 

 41m.' — are not very trustworthy, because they were deteniiined 

 by measuring the linear distance from a break in the curve 

 which was caused regularly every day about noon by taking 

 away the lamp. The exact times of these breaks were noted 

 in a book, which, unfortunately, was destroyed by the fire. Prof. 

 Milne, however, tells me that in the instalment, to which cor- 

 responds the first of the above-mentioned times, the lamp was 

 always removed within half a minute or one minute from noon 

 (Japan time). Ccmsequently, the error cannot exceed a few i 

 minutes. The duration of the disturbance was between two 

 and three hours in all the three instruments. 



If we consider that the error of the first observation is not 

 likely to exceed ten minutes, then we find, by comparing 

 Prof. Milne's observations with those made in Europe, that 

 although the .spherical distance between the epicentre of the 

 earthquake and Tokio is >w less than I7,4CX> kilometres, the 

 earth-motion reached Japan at about the same time, or perhaps 

 even a little earlier, than ft arrived in Europe. It is unnecessary 

 to point out the interest which is attached to systematic obser- 

 vations of this kind. Prof. Milne's observation is probably the 

 first in which an earthquake was noticed by seismic instruments 

 at a place so near the antipodes of the earthquake centre. .\ 

 straight line between the two points is only very little shorter 

 than the earth's diameter ; the time required for the motion to 

 pass through the globe was probably less than twenty minutes. 

 .VIerseburg, .May I. E. von Rebeur-Paschvvitz. 



Guanine in Fishes' Skins. 



In a joint paper by .Mr. J. T. Cunningham and myself (Phil. 

 Trans, vol. clx-xxiv., 1893, J^> PP- 765-812), we have ventured 

 to question the accuracy of the statement made in many texi-books 

 of physiological chemistry, that guanine occurs in combination with 

 calcium in the skin of fishes. We found that the guanine occurs 

 in the free state. In the last number of Hoppe-Seyler's Zeit- 

 schrift fiir Physiologische Chemie there is a paper by Herr 

 Albrecht Berthe, dealing with this subject, in w-hich he shows 

 that the calcium so frecjuently found with the guanine is due to 

 the presence of impurities derived from the tissues and the scales. 

 Its amount depends upon that of the impurities present, and 

 is very variable. Instead of finding 1 1 '76 per cent, required by 

 the formula of " Gtianinkalk^^ Berlhe finds less than one-third of 

 that percentage present, and even this also varies within wide 

 limits. In the paper referred to above, we found one source of the 

 I alcium was due to the presence of comparatively large crystals of 

 talcium phosphate, which are figured on p. 788 ; but there is no 

 doubt that the bulk of it is derived from the scales. 



Chas. a. MacMunn. 



Oaklcigh, Wolverhampton, May 4. 



The Oldest 'Vertebrate Fossil. 



Noticing in your issue of .^pril 11 a reference to the dis- 

 covery of specimens of Cyathaspis in the Silurian of {lotland in 

 strata equivalent to the English Wenlock, and with it the state- 

 ment that these fossils are " for the present the oldest known 

 vertebrates," I am led to call your attention to the species 

 described by myself from Silurian strata in Pennsylvania in 1885 

 (p. 48), and .again in 1892 (p. 542), in the Quarterly [otiriial oi 

 the Geological Society. I forward with this a copy of the paper, 

 from which it will be seen that the Salina (Ononduga) beds that 

 yielded PaUcaspis are older than the Ludlow (or Lower Helder- 

 berg), and that the Clinton are older than the Wenlock (or 

 Niagara). Consequently Onchtis Clintoni of the latter group is 

 thus far the oldest vertebrate. E. W. Clavi'OI.e. 



.\kron, Ohio. 



CINCE our last reference to this subject three com- 

 *-^ munications have been laid before the Royal Society. 

 They are as follows : — 



HeI-ICM, 



A Gaseous Consii i lENr ok Certain 

 Minerals.' 



• These hours .-ire Iapr\n time. 

 from noon. 



i.e. qh. easl of Greenwich, and .'jre reckoned 



.\n account is given of the extraction of a mixture of hydrogen 

 and helium from a felspathic rock containing the mineral 

 cleveite. It is show n that in all probability the gas described 

 in the preliniinarj' note of March 26 was contaminated with 

 atmospheric argon. The gas now obtained consists of hydrogen, 

 probably derived from some free metal in the felspar, some 

 nitrogen and helium. The density of helium, nearly free from 

 nitrogen, was found to be i'Sg. From the wave-length of 

 sound in the gas, from which the theoretical ratio of specific 

 heats I "66 is approximately obtained, the conclusion may be 

 drawn that helium, like argon, is monatoniic. Evidence is pro- 

 duced that the gas evolved from cleveite is not a hydride, and a 

 comparison is made of the spectra of argon and helium. There 

 are four specially characteristic lines in the helium spectrum 

 which are absent from that of argon : they are a brilliant red, 

 the D3 line of a very brilliant yellow, a peacock-green line, and 

 a brilliant violet line. One curious fact is that the gas from 

 cleveite, freed fi-om all impurities removable by sparking with 

 oxygen in presence of caustic potash, besides other fainter lines, 

 exhibits one, and only one, of the characteristic bright red pair 

 of argon lines. This, and other evidence of the same kind, 

 appears to suggest that atmospheric argon and helium have some 

 common constituent. 



Attention is drawn to the fact that on subtracting 16 (the 

 common difference between the atomic weights of elements of 

 the first and second series) from 20, the approximate density of 

 argon, the remainder is 4, a number closely approximating to 

 the density of helium ; or, if 32 be subtracted from 40, the atomic 

 weight of argon if it be a monatomic gas, the remainder is 8, or 

 twice the density of helium, and its atomic weight if it too is a 

 monatomic gas. 



On the New Gas obtained from Uraninite.' 

 Since my communication on the gas obtained from Uraninite 

 (Broggerite) was sent in to the Society on the 25th ult., I 

 have been employing the method I there referred to in several 

 directions, among them to determine whether the spectrum of 

 the gas indicates a simple or a complex origin. 



I wa-s led to make this special inquiry on account of the 

 diflTeience in the frequency of the appearance of D3 and the other 

 lines to which I referred in the solar chromosphere. For 

 instance, if we take the lines D3, 44.71, and 4302, the frequencies 

 are as follows, according to Voung ^ : — 



Dj ... ... ... ... 100 (maximum) 



4471 too ,, 



4302 3 



Hence, we might be justified in supposing that D3 and 4471 are 

 produced by the same gas, and that 4302 owes its origin to a 

 different one. 



But further experiment has given me one case in which D, 

 shows bright, while 4471 is entirely absent. I may now add 

 that an equally important line to 4471, one at 4026-5, appears, 

 with the dispersion employed, in the spectrum of Broggerite, 

 and both these lines are w ide and fluffy, like the lines of hydrogen, 

 and are apparently reversed. 



The line 4026-5 has not been recorded by Young, though, .is 

 I have staled, the frecjuency of appearances of 4471 represents 

 the maximum ; still, while this is so, the intensity of both these 

 lines in the s|x;ctra of the hottest stars is not surpassed, even by 

 those of hydrogen. Hence, opinion as to their representing the 

 same gas must be susi>ended. Further, I have photographed a 

 line at 4388 apparently coincident with another important line 

 in the same stars. Whether, coming from one source or two, in 

 these three lines seen along with D, in the gas obtained by me 

 from Broggerite, we have, it would seem, run home the most 

 important lines in the spectra of stars of Group III., in which 

 stars alone we find Dj reversed. Should these results be con- 

 firmed, the importance of the gas or gases they represent at a 



1 By Prof. W. R.imsay. F.R.S. (.ibstract). 

 - Second note. By J. Norman l.ockyer, C.B., F.R.S. 

 1 3 See " Solar Physics, " LocVyer, p. 612. 



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