NATURE 



\Feb. II, 1875 



The earlier part of the second memoir (28 pp.) treats 

 of points, lines, and polygons, and swarms with result^, 

 upon the novelty or antiquity of which we cannot pro- 

 nounce a judgment. We have then some proofs given of 

 properties of the Tricusp, which is the envelope of the feet 

 perpendicular lines of an inscribed triangle. Steiner's 

 enunciations (" Crelle," vol. 53) have been demonstrated 

 by Prof. Townsend (" Reprint from Educational Times," 

 vol. iv. pp. 13-17), Prof. Cremona (" Crelle," vol. 64), and 

 by other mathematicians.* An appendix of eleven pages, 

 entitled " Ueber Raumcurven vierter Ordnung erster Art, 

 und eine spezielle ebene curve vierter Ordnung C-'i" closes 

 the memoir. 



The last memoir on our list (39 pp.) is a very interesting 

 one, in which a great number of properties of the curve 

 are established by means of its ordmary rectangular equa- 

 tion (.1" -t-j'^)- - 2'2" {^' - J'-) = o. We should like to see 

 this memoir in an English dress. On the authority of a 

 German (riend, we may say that it is written in elegant 

 German. All three memoirs are extracted from the 

 " Abhandlungen der k. bohm. Gesellsch. der Wissen- 

 schaften " (vi. folge, 6 Band). Whether the practice 

 obtains on the Continent to any extent of thus reprinting 

 separate memoirs we cannot say, but we learn from a dis- 

 tinguished physicist that such is the case with the Vienna 

 " Transactions," of which any paper may be had sepa- 

 rately through a bookseller at a price published in the 

 table of contents. This is a laudable practice, and in 

 these columns the desirableness of its introduction into this 

 country has been more than once dwelt upon. Happily, 

 we learn from the President's address (Nature, vol. xi. 

 p. 197) that the Royal Society have the matter under con- 

 sideration. As the reasons pro and co/i have so recently 

 been given, it would be out of place here to dwell longer 

 on the matter. We hope, however, that it will be possible 

 on some terms or other to get separate memoirs in the 

 case of those societies whose publications embrac2 two or 

 more specialities. A practice obtains in some societies of 

 allowing readers of papers to have extra copies of their 

 own papers, at reasonable prices, for distribution. Possibly, 

 the best mode of proceeding at present for a specialist 

 who wants a particular paper is for him to apply to the 

 author on the chance of his having these extra copies. 



Botanischer Jalircshcrichf : Systciiid/isch geordenetes 



Repcrtorium det Botanischcn Lileratut alter Lander. 



Herausgegeben von Dr. Leopold Just. (Berlin : 



Gebriider Bertraeger, 1873.) 

 With the rapid increase of botanical literature of every 

 kind during the last few years every working botanist 

 must have proved the inconvenience of having no work of 

 reference at hand like this " Botanischer Jahresbuch," 

 and particularly those who are engaged in any special 

 inquiry involving much research and an extensive know- 

 ledge of the literature of his subject. As the preface to 

 this excellent n'snine o{ the botanical literature of 1873 

 truly says, " Almost every botanist has passed through 

 the experience of having read through bulky treatises with 

 the expenditure of much time, only to complain that it is 

 so much time lost. On the other hand, it happens fre- 

 quently enough that very important treatises appear in 

 periodicals where they are not exactly looked for by 

 botanists, and consequently frequently remain unknown 

 and unused for years." This need no longer be the case, 

 if the success which this undertaking thoroughly deserves 

 is granted it, and warrants the continuance of it from year 

 to year. 



The work has been published in two half-volumes, and 

 the first part or half-volume summarises the investigations 

 which have been made, and the literature published on 

 the various groups of the Cryptogamia, together with 

 divisions on the morphology of cells, the morphology of 

 tissues, the special morphology of conifers, the morpho- 



" There is an article " Sur I'Hypocycloide .■I trois Rebroussements " in the 

 "Nouvellcs Annales" (pp. 21-31), Janvier, 1875. 



logy of the Phanerogamia (monocotyledons and dicoty- 

 ledons), and Physical and Chemical Physiology, continued 

 in the second half- volume, which further contains divi- 

 sions on fructification and reproduction, hybridation, 

 origin of species. Lists and notices of systematic mono- 

 graphs and extra-European floras stand next in order, 

 together with Pakeobotany, treated according to the suc- 

 cession of formations, beginning with the Primary or 

 PaLxozoic formation. The other portions embrace phar- 

 maceutical botany, technical botany, botany applied to 

 forest mmagement, diseases of plants, and geographical 

 distribution. 



The aim of the editors has been to give as complete a 

 view as possible of the literature of the several subjects 

 above mentioned, and with regard to most of the depart- 

 ments this has been successfully accomplished, but omis- 

 sions occur in some of the divisions, particularly in 

 those on the cellular cryptogams and the morphology of 

 tissues. No notice, e.^., is taken of the important work of 

 Sirasburger on Azolla and the Lycopodiacea;, nor the 

 work of Juranyi on the spores of Salvinia natans. Some 

 of the omissions Dr. Just promises to rectify in the next 

 year's volume. 



In this deficient section, however, it may be observed 

 that all newly constituted species amongst the Diato- 

 maceas and fungi are carefully noted, and of the latter 

 brief descriptions are given. As an appendix to the 

 fungi appe.irs a section on the nutrition of the lower 

 organisms. 



The above-mentioned divisions of the work embrace 

 all that has been published in the time specified (1S73) in 

 the German, French, and English languages. The lite- 

 rature of other countries is treated in special sections, 

 each under the care of an editor chosen for the purpose ; 

 viz., Dutch, Italian, Russian, and Hungarian botanical 

 literature. Dr. Just laments that it has not been possible 

 to include the literature of Denmark, Norway, and 

 Sweden in this first volume. This, however, will not be 

 omitted in future volumes, a suitable editor having been 

 chosen for the purpose. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opitnons expressed 

 by his correspondents. Neither can he undertal;e to return, 

 or to correspond "with tlte writers of, refected vianuscripts. 

 A'o notice is taken oj anonymous communications.'^ 



Sub-Wealden Exploration 



In N.\ture, vol. xi. p. 267, the Rev. J. F. Blake calls atten- 

 tion to the announcement that it is proposed by the Sub-Wealden 

 Exploration Committe; to abandon the present bore-hole and to 

 begin again near the same spot. He asks why should not 

 another spot be chosen ; and suggests that it would be advisable 

 to bore much more to the north-tast, because there the PaKneozoic 

 rocks would be nearer the surface, and because at the present 

 hole we have already learnt all tliat is necesiavy. May I be per- 

 mitted to reply to these remarks ? 



In the first place, it should not be forgotten that to search for 

 coal measures, or even for the PaIa:ozoic rocks, is only one object 

 of the exploration. In a purely scientific point of view, it is as 

 important to determine the thickness and character of the Oolitic 

 strata — so far removed from their surface outcrop — as it is to 

 reach the older rocks. If it be true that the boring has been put 

 down where the Oolitic series is weU developed, then this object 

 will be the better attained. 



But there is even now no proof that the Palajozoic rocks must 

 necessarily be very deep at Netherfield. We are not entitled to 

 infer from the great development of any one member of the 

 Oolitic series that the lower members will also be well deve- 

 loped at that spot. The Oolitic rocks in the Boulonnais come 

 on in force as we recede from the Palaeozoic area of Marquise. 

 The Kimmeridge clay is well developed In the Pays de Bray ; it 

 is 1,000 feet thick near Rouen, and, on its outcrop to the south- 

 west of that city, is underlain by Lower Oolites. One might 

 therefore well have supposed that in the Pays de Bray there 



