Nov. 1, 1S66.] 



HARDWICKE'S SCIENCE-GOSSIP. 



203 



Migration of Swallows— In your number of 

 June 1, 1SG5, I asked a question about the advent 

 of Swallows to Europe, which has not been answered 

 as yet by any of your correspondents, but which I 

 am able now to reply to myself, and this extract 

 from the Jersey Times will satisfy your readers as to 

 the return route of the Hirundines Africawards ; 

 whilst, as to their advent in Europe, I may state 

 that, on the 2nd April of this year, I saw flights of 

 Swallows high up in the air wending their way 

 across this island to the same point of the compass 

 (Hampshire) as that from which they were evi- 

 dently coming when on their exodus route thence 

 on 27th October, ult., as stated in the newspaper 

 paragraph by me. As these two observations of 

 mine are of very great importance to all Ornitholo- 

 gists,' I hope you will give this a place in your serial, 

 for it tends to clear up a good deal of the mystery 

 hitherto attaching to the migration of Swallows 

 annually. — H. E. Austen, Lieut. -Colonel, Unattached, 

 and M. B. M. S. 



N. B. — The total distance to be travelled by the 

 Swallows, from the Isle of Wight to Timbuctoo by 

 the route suggested here by me, is 2,350 English 

 miles. 



" The Swallows from England returning to 

 Africa. — It was my good fortune last spring to see 

 the advent of the Swallows, as they crossed over 

 Jersey Englandwards ; and it was equally my good 

 luck, last Thursday afternoon, to witness along and 

 large flight of Hirundines just about to cross the sea 

 at St. Clement's Bay in their flight towards France. 

 It was raining at the time, and my wife and I were 

 taking shelter there from the shower, and happening 

 by mere chance to look up at the clouds, to see 

 what probability there was of their clearing off, we 

 perceived, at a great height, and above the stratum 

 of nimbus apparently, a long straggling flight of 

 Swallows, all following in one and the same route, 

 at the rate of 30 or 35 miles an hour, in a course due 

 S.S.E., as I verified by a rectified compass-bearing 

 subsequently. Now this course I have traced on a 

 map of Erance, on a large scale, and I find it would 

 lead these emigrant Swallows over that belt of 

 Erench country comprised respectively between 

 Nantes and Saumur, on the Loire, Eontcnay and 

 Poitiers, Cognac and Bellac, Toulouse and Rodez, 

 and, finally, between Perpignan and Narbonne. 

 Here, I fancy, they would turn the Eastern flank of 

 the Pyreneeau chain, at Ceret and Port Vendre, 

 and thence, skirting the Spanish shore, wend their 

 course towards that part of the African coast which 

 lies between Oran and Algiers, and so reach, finally, 

 their winter quarters, south of the Atlas range, 

 amid those genial oases of intertropical Africa, 

 where they will build nests, and rear another brood, 

 as well as moult, before these sweet harbingers of 

 the European summer revisit our shores again. The 

 late very heavy and continuous rains in the West of 

 England have, no doubt, accelerated the exodus of 

 these birds, and I expect to find that the Jersey 

 Swallows will follow suit next week. — A Field 

 Officer and M. B. M. S." 



San GTJiN aria.— The "Sanguinaria" of the "Bra- 

 zilian Sketches" (p. 239 of Science Gossip), is 

 probably Poinsettia pulcherrima, a magnificent plant 

 common enough in our stoves, and flowering through 

 the winter. I expect to have at least half a dozen 

 in full glow in about a month from this time. The 

 branches are terminated by a flat radiating crown of 

 ovate leaves (bracts) of glowing scarlet, the whole 



as large as the area of a dinner-plate, or larger. 

 From the centre of this disc proceeds a cluster of 

 small orange-coloured flowers, which may be com- 

 pared to cups. Poinsettia, too, is a genus of 

 tropical America. — P. H. Gosse, Torquay. 



Asphalt Varnish.— I also have tried to make 

 the asphalt and India-rubber varnish as recom- 

 mended by Mr. Davies in his book, but with no 

 better success than "J. H. McK." I did, as Mr. 

 Davies tells us, procure the best asphaltum and the 

 best mineral naphtha I could obtain, and used the same 

 quantities he gives. I first pounded the asphaltum 

 and put it into a stoppered bottle with the naphtha, 

 and let it stand for two or three days, but the 

 naphtha merely got discoloured ; I then submitted 

 it to heat — in fact, almost boiled it, — but with no 

 better result. I have had some in a stoppered 

 bottle for about four months, and there is no appear- 

 ance at present of its being dissolved. I have, since 

 I failed in that experiment, tried one of my own, 

 which has answered my purpose very well for mount- 

 ing in fluid. I dissolve the asphaltum in turpentine, 

 and- the India-rubber in mineral naphtha, and mix ; 

 if it gets too thick in working add turpentine. It 

 makes a very adhesive cement, and, with baking a 

 short time, sets very hard. If "J. H. McK." will send 

 me his address I will forward a slide put up with 

 my varnish, when he will be better able to judge of 

 its quality. — /. R., 2, Bast Cottages, Willington 

 Road, Clapham, S. 



Eor Dissolving India-rubber, coal naphtha 

 must be used, as the common wood naphtha is 

 useless for the purpose.— W. K. Bridgman. 



Asphalt Varnish. — If "J. H. McK." will 

 break up his asphaltum into a fine powder, put the 

 bottle containing it and the naptha into a water- 

 bath, and heat it up to about 190°, the asphaltum 

 will readily dissolve. The difficulty I experienced 

 with Mr. Davies's receipt was to dissolve the India- 

 rubber, which baffled all my efforts, only swelling to 

 a jelly-like mass, and compelled me to procure it in 

 a dissolved state from the makers of India-rubber 

 goods. Mr. Davies has written a very useful book ; 

 but how to make up such compositions as the above 

 requires a little further instruction. Nor would it 

 be easy to dissolve arsenious acid in water, as named 

 in another place. — E. G. M. 



Mounting in Balsam and Chloroform.— Can 

 any readers who have had some experience in the 

 matter say if the majority of objects mounted in 

 balsam and chloroform keep as satisfactory as if 

 mounted in balsam only ? If so, all need of heating- 

 apparatus is at an end, and mounting in balsam made 

 easy, the convenience of usiug it, thinned with the 

 chloroform, being very great. Two or three delicate 

 objects may even be laid, side by side, on a slide, 

 the cover put on, and the mixture (a drop being put 

 on one side of the cover-glass) allowed to flow under 

 by capillary attraction, without disturbing the 

 arrangement of the objects. My experience of 

 mounting in balsam confirms the remarks of your 

 correspondent, " T. B.," pages 175 and 209. Fol- 

 lowing the directions there given, there is little fear 

 of air-bubbles remaining after the slides have been 

 mounted a few days, particularly if the balsam is 

 thin enough to use cold, as advised by Mr. Brittaip. 

 Unfortunately, however, it will not remain long in 

 this state, but soon gets too thick ; but if it may, 

 without disadvantage, be thinned with chloroform, 

 the great desideratum is gained.— i?. G. M. 



