46 



HARDWICKE'S SCIENCE-GOSSIP. 



The Laburnum was called Bean-trefoile tree in 

 the time of Gerard, because the seeds are shaped 

 like the bean, and the leaves like the trefoil. It had 

 also the name of Peascod-tree in that age, but which 

 lias long given way to that of the Latin Laburnum, 

 which Haller says is evidently derived from the 

 Alpine name, L'aubours. In French it is named 

 Cytise des Alpes. Abotcrs, and Faux Ebenier, because 

 the wood was often used as a substitute for ebony. 

 — Sylva Florifera. 



The Birch.— The books which Numa composed 

 about 700 years before Christ were written on the 

 bark of the Birch-tree ; and if we may depend on 

 the testimony of Pliny and of Plutarch, they were 

 found in the tomb of that great king, where they 

 had remained 400 years. — Sylva Florifera. 



Dragon-flies in London. — I feel obliged to 

 your correspondent J. P. S. C. for his plausible 

 suggestion ; and I must own that, at all events, a 

 step in the right direction has been taken to clear 

 up the mystery that surrounds the appearance of 

 the Dragon-fly in our crowded thoroughfares. No 

 doubt some of your readers have noticed, standing 

 in a small plot of ground within a very few paces of 

 Bishopsgate-street Church, a small fountain sur- 

 rounded by a pool. Now last spring some flags and 

 other aquatic plants were introduced into this pool ; 

 and it is highly probable that if their roots had 

 been carefully examined, some eggs, or even a 

 stray larva or two, would have been discovered. 

 There may be many other little fountains of this 

 kind in the metropolis, but I simply mention this 

 particular one on account of its being but a mere 

 stone's throw off Threadneedle-street, where, it 

 will be remembered, I mentioned that a Dragon-fly 

 had been captured. With reference to the dragon- 

 flies that have from time to time made their appear- 

 ance in town, having wandered from their native 

 haunts to seek their fortunes in our busy streets, I 

 think it improbable, though quite possible, that that 

 could have been the case ; and perhaps it is quite 

 out of the question to suppose for a moment that 

 such strong fliers could have been carried away by 

 the wind. A friend of mine has suggested that they 

 may have been brought down the Thames by boats 

 that had been moored amongst the reeds ; but I 

 believe that could not have very well been the case. 

 However, it is evident that the question as to how 

 and by what means these Dragon-flies made their, 

 appearance in the metropolis has not yet been 

 satisfactorily answered ; and I fear it will remain 

 an open question till the summer brings us fresh 

 opportunities of investigating the matter more 

 closely. — S. A. Harry. 



Pigeon-Posts. — Perhaps it may interest some of 

 your readers to know how the pigeon-post is man- 

 aged. The pigeons to return to Paris are taken 

 from that unfortunate city by balloon. The letters, 

 &C, to be sent back by the birds are reduced to a 

 very small size by photography, and secured to the 

 centre tail-feather, which is stationary during flight, 

 and carries the burden easily. The foliowingex- 

 tract from the Daily News of Jan. 13th will show 

 what a large number of messages one pigeon can 

 carry: — "Bordeaux, .Jan. lUth.— M. Feillet, the 

 director of the pigeon-post, tells me that no less 

 than 30,000 public and private letters were dis- 

 patched to Paris to-day by one pigeon. Duplicates 

 of these were sent by two other pigeons; so that in 

 all 90,000 microscopic copies of letters were made. 

 — 11. Budge. 



Aquarium Query. — For the last three months I 

 have kept a carp and two gold-fish in my aquarium, 

 which holds a little more than three gallons of 

 water, and have planted Anacharis ahina&tnim 

 (Water-thyme), Afyriophyllum spicatum (Water-mil- 

 foil), and Vallisncria spiraUs,m mud,'whichiscovered 

 with small stones to the depth of about \\ inch. 

 I have also in it snails, beetles, &c. On some 

 days the water is beautifully clear and transparent, 

 and, perhaps, the next morning, without any appa- 

 rent reason, I find the water so thick and turbid I 

 can hardly see the fish : in about three or four days 

 it becomes clear again. The change, so far as I 

 can judge, takes place in the night, and I am quite 

 certain does not proceed from the fish burrowing 

 into the mud. In vain have I tried to account for 

 this change, and am quite at a loss to find out its 

 cause. Does it proceed from the fish, the weeds, 

 the snails, or the beetles ? Can any of the readers 

 of Science-Gossip solve this difficulty ? — John B. 

 Luson, Bus hey Park Cottage, Teddington, S. W. 



The Dahlia was but little known in England 

 until after the year 1814, when the peace enabled 

 our nurserymen to obtain an additional supply both 

 of roots and seeds from France, where the cultiva- 

 tion of these plants had been more attended to than 

 in this country. The Count Lebeur, at Paris, and 

 M. Otto, at Berlin, were the principal foreign ama- 

 teurs who cultivated the Dahlia previous to 1809. — 

 Flora Historica. 



" Eye-stones."— When a girl I frequently visited 

 a lady who had some of these stones ; they were 

 brought from Jamaica or Sierra Leone, I forget 

 which. For fifty years I have been wishing to know 

 what they were, but have not met with any one who 

 knew anything about them, or had seen them. My 

 own opinion is that they are not stones, and certainly 

 from their form cannot be shells. I believe they are 

 opercula. I have met with several of the exact 

 form, though minute in size, in sand shaken out of 

 sponge, and 1 have an operculum an inch in 

 diameter of the precise form. — F. C. B., Streatham 

 Hill. 



Eye-stones {Phasianella Pulliis). — The eye- 

 stones mentioned by T. C. Izod, in the January 

 number, p. 21, are no doubt the opercula of some 

 species of Turbo, or one of the allied genera, per- 

 haps Phasianella. They may possibly be intended 

 to defend the molluscs against the attacks of crabs 

 and other enemies. The widely distributed Phasia- 

 nella Pullus is, I believe, the only British species 

 possessing this kind of operculum, which usually 

 belongs to inhabitants of warmer seas. Perhaps 

 some of your readers can explain this singularity. 

 My own idea is that this species, which is found 

 abundantly in the tropics, may be a relict on Our 

 coasts of a warmer epoch. — B. Egerton, 31, Victoria 

 Boad, Kensington. 



Wno Killed Cock Rorin ?— In answer to 

 correspondent "G. R. " the entertaining and 

 popular story of "Who Killed Cock Robin? was 

 written by Rev. — Mosely, who is still living, and 

 is said to have received a very large sum of money 

 from the sale. — II. 31. Damon.. 



Darkling Spiders. — Two or three days after 

 I had read Mr. Clifford's paper on "Darkling 

 Spiders" in Science-Gossip for January, p. 12, 1 

 came upon the following remark in the first volume 



