HARDWICK&S SCIENCE-GOSSIP. 



185 



me in my last letter, is certainly ingenious, but is 

 scarcely satisfactory in all points. In my " gather- 

 ing " the most searching scrutiny failed to reveal the 

 presence of the funnel rotifer in the first instance. 

 Neither was there any other sufficiently large to 

 attack the full-grown Euglence with which the water 

 teemed. These gradually disappeared until scarcely 

 more than one could be drawn from the vessel con- 

 taining the water, whilst a whole army of funnel 

 rotifers were sporting away their short life. My 

 suspicion is, at present, that these bulbed Euglenre will 

 ultimately prove to be the larvae of Hydratina lenta, 

 or common funnel rotifer. I enclose a rough pencil 

 sketch of three forms of the Euglena observed by me. 

 At the first, No. 1 was the shape of most of those 

 I gathered ; these subsequently became fewer, and 

 No. 2 was then the predominating form. A short time 

 afterwards, the flagellum of the No. 2 disappeared, 

 and a wreath of very delicate cilia (No. 3) was clearly 

 discernible. [The objective used by me is a Beck 

 Jin. with No. 3 eyepiece, giving an enlargement of 

 nearly seven hundred diameters.] — F. Jas. George, 

 Chorley, Lane. 



How to Make a Comtressorium. — Cut a couple 

 of pieces of wood the size of a glass slide, with two 

 small arms projecting from the middle on each side, 



Fig. 147.— Sketch showing details of Compressorium. 



with a hole bored through each. Get two screw 

 paper-binders, the largest size : and some glass slides. 

 The object to be compressed is placed 

 between the two glass slides ; these are 

 placed between the pieces of wood, and the 

 whole screwed together with the binders 

 which pass through the whole. The only 

 caution needed is to place the holes suffi- 

 ciently near the edge to admit of the ring of the 

 binder standing out beyond it. Any number of 

 slides, and therefore of objects, can be put in it, and 

 the pressure regulated on either side without moving 

 the object. The outside may be of brass lined with 

 baize. — H. Field, Blackett, Cambridge Mission, Delhi. 



ZOOLOGY. 



Birds in London.— To lovers of nature compelled 

 to spend the best part of the year in London, it is 

 very pleasant to get a glimpse, however occasional, of 

 the birds, and I think their appearance is not so 

 exceptional as might at first be imagined, for during 

 the three years I have been living on and off in 

 London, I have seen as many as twenty-four species. 

 The inevitable house sparrow of course would head 

 the list as regards frequency of occurrence ; starlings 

 and rooks are tolerably common ; and I have once 

 or twice seen jackdaws. Blackbirds and song 

 thrushes may be seen in all the parks ; the missel- 

 thrush is rather rarer ; and during the late severe 

 winter I once saw a redwing thrush so busily search- 

 ing for something eatable on the frost-bound earth 

 that I was able to approach within a couple of yards 

 of it. Of the warbler family I have seen the white- 

 throat-hedgewarbler, the robin, the wren, the willow 

 warbler, and on one occasion the blackcap. The linnet 

 and the chaffinch, the skylark, the pied wagtail, the 

 blue tit, are, as far as I have observed, the only 

 London representatives of their respective families. In 

 Battersea Park a happy little family of moorhens may 

 be seen. I have once or twice noticed the common 

 gull, once, the tern, flying over the river between 

 Vauxhall and Chelsea Bridges, and on one occasion I 

 have seen the great black-backed gull flying slowly 

 down the river, near Lambeth Bridge. Swallows are 

 sometimes to be seen, especially in Battersea Park ; 

 twice lately I have seen swifts circling about, on one 

 occasion over the Horse Guards, on the other over 

 the river near Chelsea Bridge. I should be inclined 

 to attribute their appearance to their having had to 

 extend their hunting grounds, on account of insect 

 life being comparatively scarce, by reason of the 

 long- continued unfavourable weather. — IV. H. Legge. 



Influence of the Wet Season on Butter- 

 flies. — Not for several years have I observed the 

 summer brood or flight of butterflies (the emergence 

 of which usually occurs about the end of May or the 

 beginning of June) to be so deficient in numbers. The 

 species that have suffered most from the unfavourable 

 spring are those which are single brooded, and con- 

 fined to a special habitat. In some of these, we may 

 suspect there will be even more scarceness noticeable 

 in 1880, through the deficiency of parents this year. 

 Thus, take such an example as some Fritillary 

 furnishes, say Argynnis Euphrosyne. If some wood 

 in which it breeds furnishes in average years a thousand 

 perfect insects, and this year only two or three 

 hundred came out, owing to the death of many larvae, 

 the number of eggs deposited will perhaps be 25 

 per cent, less than in 1878. We can easily understand 

 how it is that some species disappear for long periods, 

 or die out, when they had had to endure a succession 

 of unpropitious seasons. — J. R. S. C. 



