438 



NATURE [March 13, 1902 



regard the use of the terms "sporangium," "macro- 

 spore," " microspore " as unnecessary, seeing that the 

 book deals only with the flowering plant ; and why 

 " oosphere " and not " ovum " ? 



In the second part short chapters explain the Linn;can 

 and natural systems of classification, the distribution of 

 plants, and ^'ivc general directions for field work. 



The physiology is the least satisfactory part of the 

 book. The plan adopted of giving experiment, result 

 and conclusions to be deduced therefrom is eminently 

 good. But many of the experiments arc open to serious 

 criticism, as in some cases the apparatus is not practical, 

 in others the deductions are unsatisfactory. For instance, 

 apparatus is figured on p. 126 to show that plants take 

 in oxygen. The apparatus shown would certainly allow 

 leakage of air ; the potash would not absorb much 

 carbon dioxide, and in so far as it did, this would partly 

 account for the change in the manometer ; further, the 

 seedlings shown in the figure would photosynthesise 

 unless placed in the dark. The three subsequent figures 

 also show apparatus which is not workable. Despite 

 these faults and one or two erroneous statements, the 

 book is so vigorous and well compounded that it may 

 be strongly recommended to school teachers as one 

 which is eminently suitable for beginners in botany. 

 intuitii'e Suggestion. 15yJ. W. Thomas. Pp. x -(- 160. 



(London : Longmans, (ireen and Co., 1901.) Price 



y. 6ii. net. 

 It is difficult to know how far Mr. Thomas takes himself 

 seriously. His book is called a "New Theory of the 

 Evolution of Mind," and certainly contains some very 

 novel and curious statements both about the past and 

 about the future of mankind. He has, however, no very 

 clear notion of the difference between saying a thing and 

 proving it, and many of his most remarkable assertions 

 are made without any serious attempt of proof His main 

 thesis appears to be that the processes of the inorganic 

 and organic worlds alike are the consequences of a series 

 of quasi-hypnotic "suggestions" on the part of a "great 

 first cause." He takes, that is, a few unfamiliar and 

 very imperfectly understood facts of experience and 

 makes them the basis of a theory of experience as a 

 whole. Apparently he has never even asked himself 

 whether there is any evidence to show that a creature 

 without a nervous system would be amenable to "sug- 

 gestion " at all. The argument from the miraculous 

 narratives of the Bible, on which he lays great stress, is 

 deplorable alike from the standpoint of logic and of 

 piety. From the logician's point of view, the alleged facts 

 are insufficient as a basis for a theory of nature, and 

 from that of the believer they lose all their moral signifi- 

 cance by being- degraded to the level of mediumistic or 

 hypnotic "phenomena." A. E. T 



Jahrbuch der Chemic. Herausgegeben von Richard 



Meyer. Jahrgang, 1900. Pp. xii -F 565. (Brunswick: 



F. Vieweg und Sohn.) Price 15 mk. 

 Thouc.h somewhat later in the time of its appearance, 

 this valuable publication is happily not much thicker 

 than its precursors, and the \olume before us gives in 

 reasonable space an excellent suminaiy of the chief 

 advances in chemistry and applied chemistry recorded 

 in the year 1900. The labour of writing is distributed 

 among authorities of the highest competence, and the 

 result is correspondingly satisfactory. It is true that 

 the information is in a highly condensed form, but the 

 present writer is able to say of the subjects on which he 

 is at all qualified to speak that they are dealt with in 

 summaries which bear the impress of informed writers 

 rather than hack abstractors, and that they will continue 

 to serve well the useful purpose of assisting all those who 

 are engaged in the difficult task of keeping themselves 

 moderately well informed of chemical progress. 



A. S. 

 NO. 1689, VOL. 65] 



LETTERS TO THE EDITOR. 

 ( The Editor does not liold himself responsihlc for opinions ex- 

 pressed by his correspondents. Neilh,r can he underlal:/-. 

 to return, or to < 01 respond with the writers of, rejenei 

 manuscripts intended for this or any otiier part of Nature. 

 No notice is taken of anonymous communicat ions.'i 

 I 



{ Earthquake Observations in Strassburg. 



DURINC, the last twelve mdnlh";, i>n more than one occasion I 



! have heen asked why it is that at ilie Kaiserlichen Hauplstation 



(iir lirdbebenforschung in Strassburg one type of instrument 



j records earthcjuakes so very much more frequently than other 



I types of instruments give records, although they are all inslalled 



in the same building. An answer to this is apparently to be 



lound in an analysis of the Strassburg registers. 



For example, in January 1901, a von Rebeur-Ehlert 

 apparatus, which consists of three horizontal pendulums oriented 

 at 120° to each other, which reflect beams of light on to a 

 photographic recording surface at a distance of about three 

 metres, yielded twelve records, only five of which were noted by 

 a single component horizontal pendulum of the type adopted by 

 the British Association and now in use at very many stations 

 round the world. This latter apparatus was therefore quiescent 

 on seven occasions when we should have expected it to have 

 been inaction. On looking at the registers, we first oliserve that 

 these seven disturbances were all exceedingly small, and two of 

 them were only noted in Strassburg. Considering this 

 latter fact, in conjunction with the facts that they are found 

 in the traces from an instrument with a very high multiplication, 

 subject to so-called " Mikroseismische Unruhe" (air tremors?), 

 and that a blur maybe formed in the photographic record by a slight 

 flare in the illuminating apparatus, it seems a bold proceeding to 

 enter such records (January 17 and 26) as being earthquakes. I 

 doubt their seismic character and consider that their entry ought 

 to have been accompanied by some qualilicalion. So much lor 

 two out of the missing seven. Two others (January 8 and 30), 

 although not recorded by the British Association type of instru- 

 ment in Strassburg, were recorded by similar instruments in 

 Britain and at stations in other parts of the world. That they 

 were not recorded in Strassburg, but were recorded all round 

 Strassburg, suggests the idea that the instrument as installed at 

 the Ilaupt.station has not the desired amount of sensibility, and 

 if this is the case it is not remarkable that this form of instru- 

 ment as used in Strassburg should fail to record very small 

 earthquakes. 



As another illustration let us take the month of August, when 

 the Rebeur-Ehlert pendulums gave twenty-four records, out of 

 which the British Association seismograph is adveriised as 

 only having responded to four. A glance at the registers for 

 stations in Britain and other countries shows that this number 

 should be increased to seventeen, leaving a balance of seven, 

 which, if they all are earthquakes, are for the most part 

 peculiar to Strassburg, and as such have in my own mind a 

 doubtful character. 



Another point connected with the Strassburg registers relates 

 to the determination of origins. To identify a .seismogram 

 obtained at Strassburg on September 17 at 4.30 a.m. as con- 

 nected with an earthquake which shook a small portion of 

 the north of Scotland at about 1.25 a.m. on that morning is 

 asking us to believe more than our reason can accept. Even 

 had the liauptstation been .situated in the south of Scotland itself, 

 it is very doubtful whether its horizontal pendulums would have 

 responded to a local shock originated in the northern part of the 

 same country. John Mil. ne. 



March 3. 



Proofs of Euclid I. 5. 

 SeveraI- writers have lately expressed their opinions in favour 

 of replacing the present proof of this proposition by an alterna- 

 tive proof based on the supposition that the bisector of the 

 vertical angle of the isosceles triangle is drawn, irrespective of 

 the fact that no construction has been given for drawing this 

 bisector. Now there may be some advantage in using a " hypo- 

 thetical construction " to prove a proposition, where its avoid- 

 ance necessitates a long and tedious alternative proof In the 

 present instance the artifice is absolutely unnecessary, as the 

 proof can be simplified in any of the following ways, A being 

 the vertical angle of the isosceles triangle ABC : — 



