22 



SCIENCE-GOSSIP. 



:Jan. 1, 1866. 



NOTES A1TD aUEEIES. 



Plaster Casts.— Can you tell me where I can 

 find any remarks on the making of plaster casts ? I 

 want to take some casts of skulls, teeth, and other 

 hones. — /. 67. 



To Kill Slugs.— Can any of your readers inform 

 me what chemical preparation it is which, when 

 dropped upon a living slug, destroys its vitality, 

 but preserves it with tentacles extended and colours 

 true as if it were alive?— J 1 . C. Y. 



Convocation or Sparrows.— Passing up St. 

 Dunstan's Hill to-day, at 4 p.m., I descried a flock 

 of sparrows on two trees, about 500 or 600 in num- 

 ber. They made a great noise for about ten minutes, 

 and then all flew off, creating quite a sensation 

 among the people. Is such a thing very common 

 (especially at this season of the year) ? And why 

 do they all flock, and then fly off if it is not com- 

 mon ?— /. A., jun. Dec. 12, 1865. 



Pees and Wasps. — In several places in Belgium 

 the same has been observed as in England— that 

 wasps were not to be seen, and that bees attacked 

 the fruit. — B. 



Good Cement.— H. J. B. asks if any one can 

 recommend a good cement for aquaria ? 



ElBRE OF THE COTTON PLANT.— Would it not 



be possible to extract the fibre of the stem of the 

 cotton plant (Gossypittm herbaceum, fye.) ? I believe 

 this is worth an investigation, and I recommend it 

 to all who are acquainted with cotton growers. I 

 tried a small delicate stem, put here in open 

 ground, and got sonic fibres by beating it.—Ber- 

 nwiin, Melle, near Ghent. 



[It has been done. Specimens from India were 

 shown at the Exhibition of 1S62— Ed. S.-G.] 



Visitation of Spiders.— It may interest your 

 northern correspondent and others to learn that the 

 spiders alluded to at page 2S2 of your December 

 number have visited the south. On returning from 

 chapel after the morning service on the 12th Novem- 

 ber last, I observed the railings from St. Thomas's 

 Street to one of the entrances to Victoria Park 

 swarming with almost any quantity of them ; but, 

 strange to sav,_ I could not find a single specimen on 

 the leafless twigs of the trees in the park, and the 

 railings beneath them had only here and there one. 

 They were very tame, running about the hand 

 freely, and leaving it by attaching a thread to its 

 margin, and so dropping down five or six inches, 

 pausing thus for a moment, and then, with almost 

 the speed of a winged insect, mounting high in the 

 air, where their intensely black bodies could be seen 

 in the bright sunlight some yards away. Accepting 

 the belief that the aerial spiders make their flights 

 by the lightness of the silk they throw off, it would 

 be interesting to learn— first, how our little visitors 

 contrived to detach the thread from the hand, or 

 whether they merely held on by it while they spun 

 another thread that was free ? Secondly, why the 

 thread from the same creature at one time is a mere 

 rope of suspension, and at another acts the part of 

 a balloon ? Is it possible that the spiders capable 

 of making these atmospheric ascents have some 

 means, hitherto unknown, of inflating the air sacks 



or other part so as to reduce their specific gravity ? 

 I spent some time the following morning in examin- 

 ing the railings, ground, and crevices in the locality 

 where the previous clay they had been so plentiful, 

 and yet with the help of ten years' experience in such 

 hunting I could not find a single individual. Their 

 threads were there, stretching from point to point 

 like fairy telegraph wires, that might have been put 

 up by some joint-stock enterprise from the realms 

 ot Queen Mab ; but of the workmen I saw none, 

 alive or dead. Their task completed here, on what 

 other fields has their great Maker employed them ? 

 —W.E.Hall. 



Atmospheric Phenomenon— While travelling 

 from Oxford, on the London and North-Western 

 Railway, on the 20th July, I witnessed what, to me 

 at least, was a novel phenomenon. The sun was 

 4 or 5 degrees above the horizon, the time being 

 7.10 p.m. In the east a dull haze extended some 

 or 7 degrees above the horizon, and terminated in 

 light flocky clouds ■ above these the sky was clear. 

 Exactly opposite the place of the sun a beam of 

 light shot up from the horizon, extending across the 

 haze and clouds as far as the clear sky above. In the 

 course of about a minute three or four more beams 

 became visible, apparently radiating from a point, 

 situated as far below the eastern horizon as the sun 

 was at the time above the western. The most 

 southerly of the beams appeared faintly tinged with 

 prismatic colours. I turned towards the west, 

 thinking the sight I had witnessed must be a 

 reflection of the "Moses' Horns," so often seen 

 when the sun is on the point of setting, but could 

 not see anything of the kind. The" appearance 

 lasted, with varying intensity, for about ten minutes, 

 fading away gradually, and quite disappearing before 

 the sun had set. After the sun was below the 

 horizon, a broad streak of rosy light filled the space 

 before occupied by the beams, as though Aurora, 

 having mistaken the hour, was about again to open 

 the gates of day before Apollo had had time to 

 repose. — IF. S., Buckingham. 



The Spawn of Doris— Would the spawn of 

 the Doris (Boris phlota), deposited in my tank. 

 ever hatch ? If so, would the young ones grow in 

 an aquarium ? The Doris spawned on the 1st of 

 November. Could any of your correspondents 

 answer the above questions ?— IF. B. 



Preserving Birds with Wood Acid.— Mr. 

 Newton, of Cambridge, says in his "Hints on 

 making Collections of Eggs ": " Birds may be pre- 

 served entire by pouring a few drops of pyroligneous 

 acid down their throats.'' I presume this would 

 only keep them for a time, until they can con- 

 venicntlybe skinned. Or would it entirely preserve 

 them without any other process ? Perhaps some of 

 your correspondents have tried the plan, and could 

 speak as to its results. — JF. F. Saunders. 



China Grass. — I believe different nettles are 

 known under that name. According to Dr. Blume, 

 the name of tchoum is given by the Chinese to 

 Bcchmcria spicafa, Thunb. ; and to B. longispim, 

 Steud. ; the Bhea of Assam is B. nivea and 

 B. tenacissima, Gaudich. ; the tameh, rami, &c, 

 of the Malay is B. tenacissima. Dr. Blume says 

 (in Mus. Ludg. Bat.) that B. tenacissima is pro- 

 duced by cultivation from B. nivea. — B. 



[All these names do not represent distinct species. 

 Bo;hmeria nivea includes B. tenacissima— ^T>. S.-G.] 



