362 



NATURE 



\August 30, 1877 



If anything could demonstrate the propensity for fly-catching in the most marked degree. You wUl see that a moth has been 

 known to exist in this class of plants, surely this specimen does I entangled by the hairs of one of the leaves, which leaf has curved 



itself right over the moth in the most determined fashion. Tliere 

 is every appearance of a struggle having taken place which ended 

 in the defeat and destruction of the moth. 



This specimen is, I should imagine, a very typical one, and as 

 such I have sent a copy to Mr. Darwin, Wright.Wilson 

 Birmingham 



The Radiant Centre of the Perseids 

 From twenty meteors, mostly with streaks, I deduced the 

 radiant point at R. A. 40°, Dtc. 56" N., August 3-7. On 

 August 10 1 saw a larye number (fifty-seven per hour) ot Perseids, 

 many of them with shfirt tracks rear the focus, and almost inva- 

 riably with streaks, from 43° + 58°. On August 12 I observed 

 quite an outburst of precisely similar meteors from a sharply- 

 defined centre at 50° -1- 55°, and registered fourteen of them, but 

 many others were noted between I2h. and I4h. On the l6th, 

 between the same hours, I sav/ five paths close to a radiant at 

 60° -)- 59°. These had streaks and apparently exhibited the 

 same features of motion, colour, &c., as those recorded on the few 

 preceding nights. Can these four positions represent one and 

 the same system of Peiseids with an apparent displacement of the 

 radiant centre on the several nights of observation ? The places 

 may be regarded as accurate for the dates, and though quite 

 possibly they are separate show-ers, it is at least singular they 

 became so well marked one on each night. If the positions 

 include the same system then the focus of divergence appears to 

 have shilted from 40° + 58° on the 3rd-7th to 60° -I- 59 ° on the 

 16th, so that while the declination remained nearly the fame the 

 R.A. had advarced twenty degrees, which in D. 59° N. is 

 equivalent to ten linear degrees of space. 



It is a capital plan while observing and mapping meteor tracks 

 to hold a perfectly straight rod in the hand, and directly a meteor 

 is seen, to project the rod upon its apparent path, carrying 

 the eye back in the same line of motion and noting the exact 

 point with reference to stars upon which it converges. In 

 the case of slow meteors or meteors with streaks, this is a very 

 accurate method and especially to be recommended in regard to 

 paths presumably a long way from the radiant. Eye-esti- 

 mates are necessarily less exact, for while the position of the 

 track is being noted the more important feature of direction is 

 inaccurately remembered. \V, F. Denning 



August 17 



Fish Commensals of Medusae 



In the numbers of Nature for July 19 and 26 (pp. 227, 248) 

 are commurications respecting fish-sheltering Medusje. The 

 Trochurus in Europe appears to be a commensal of the Acaleph 

 as well as the Pollochius. In the eastern waters of the United 

 ( States, however, so far as I am aware, the Stromatoid fish 

 Poronotus smiilis {Stru!?iatetts similis of some authors) seems to 

 be the most common, if not the only associate, of several 

 acalephs, viz., Dactylonietra quinquecirra, Zygodactylon green- 

 landica, and Cyar.ea nrctiea. Under the umbrellas of these spe- 

 cies smaliyV;'(7«(V/ are to be found in the late summer swimming, 

 sometimes even to the number of twenty or more, but generally 

 wuch ;. . r, Mr, Alexander Agassiz, in his " Sea-side Studies," 



mentions the occurrence of an undetermined "Clupeoid" fish, 

 but no other, under the umbrella of Daetylometra quinqueeirra ; 

 the identification is probably erroneous. At least my own obser- 

 vations were made in the same region and at the same time of 

 the year as Mr. Agassiz's, and only the Poronotus was seen. 

 More detailed information respecting this association may be 

 found recorded by Prof. Verrill in the " United States Commis- 

 sion of Fish and Fisheries" reports, Part I., pp. 449-450, 1873. 



Theo. Gill 

 Smithsonian Institution, Washington, August 6 



Science in Spain 



I THINK it may iivterest the readers of your journal to have 

 some slight idea of the state of natural sciences in Spain. Science 

 is universal, and the efforts made by a nation which has been 

 separated by centuries of intolerance and indifference from the 

 movement and scientific life of other countries, cannot fail to 

 be looked upon with indulgent eyes by those who cultivate 

 science. 



Of the three great branches into which we may divide natural 

 science — physics, chemistry, and natural history, the first is in a 

 most backward state in Spain. In almost all the professorships 

 where this science is L-iught, the instruction given is so out of date, 

 that no mention is made of the modern theory of the correlation of 

 forces or thermo-dynamics, and the text-books used are French 

 works, now quite obsolete. In every one of our upper schools — 

 Institutos de 2da Ensiiianza — there is a professor who teaches 

 physics and chemistry conjointly, who is instructed to go through 

 a course of these sciences, which are reduced by this means to 

 their lowest possible expression. In our universities, there exist 

 classes in which an amplification of physics is taught ; this study is 

 part of those required for the preparatory exercises (or the faculty 

 of medicine. This course, if we take into consideration the know- 

 ledge brought by the pupils who attend it, is more an explana- 

 tion of what they ought to have learnt than anytliing else. At 

 the Madrid University .lione, there is a class of "imponderable 

 fluids ; " the name in itself suggests an idea quite out of date at 

 the present day. At the same university there is also a class of 

 mathematical jihysics, but it does not form part of the studies 

 required to receive a doctor's degree in the physico-chemical 

 sciences, and is only included in the mathematical sciences. 

 This is unfortunately all the oflicial instruction on the subject 

 which is given in Spain. Almost all the professors follow the 

 theories which were generally admitted before the discoveries of 

 Grove, Mayer, Rankme, Clausius, Tyndall, aird Hclmholtz. 



During the Republican Government in Spain, it was decreed 

 to reorganise these studies in a manner more in accordance with 

 modern ideas, but the short rule of this reforming government 

 prevented this plan from being carried out, or conquering the 



