HARDWICKE'S SCIENCE-GOSSIP. 



93 



in ordinary daylight the shadows are grey. If the 

 light contains any tinge of yellow, inclining to orange, 

 the shadow will contain a tinge of blue in the same 

 proportion. Since the yellowish light of gas contains 

 comparatively few blue rays, of course all purely 

 blue colours nearly disappear when the gas is lit : but 

 that is tlie very reason M'hy the shadows have a blue 

 tinge, and that is the only way in which the blue 

 tinge could arise. Tv.'o simple experiments will 

 illustrate this. At the time of sunset in autumn, 

 when the clouds are all aflame with rosy light, it will 

 be found that the shadow of a pencil or finger, on 

 white paper, is so decidedly green, that it is hard 

 to believe the appearance is illusory. Again, if 

 the green Venetian blinds be nearly closed on a 

 bright day, so that all the light which enters is re- 

 flected from their surfaces, and is therefore green, 

 the shadow will be found to have an equally strong 

 rosy tinge. — W. B. G. 



Colours of Shadows. — The blue colour of the 

 shadow thrown by gas during daylight, may, I think, 

 be observed with all ordinary artificial light, but at 

 the same moment the shadow of the same object, or 

 of adjacent ones, thrown by the daylight will be seen 

 to be yellow-brown. The cause I take to be that the 

 artificial light is yellow, and that in the shadow 

 thrown by it, where the yellow light is absent and the 

 daylight only seen, the object illuminated by day- 

 light alone looks blue by contrast, whereas in the 

 other shadow, where the daylight is more or less 

 absent and the yellow light alone seen, it looks yellow- 

 brown by contrast or complementary colour.— 

 Albert D. Michael. 



Cyclas cornea.- — Is this creature wholly or 

 partially carnivorous ? Having had reasons for an 

 answer to the above question, I made a limited search, 

 but did not succeed in finding the required informa- 

 tion. A few days since, a living frog was brought to 

 me witli a full-sized specimen of this shell-fish attached 

 to one of its toes, having been found upon a bank by 

 the side of a canal. Upon examination the frog 

 appeared to be suffering very much from its intruder ; 

 its eyes very red, and it moved its leg backwards and 

 forwards evidently tiying to get rid of cyclas. After 

 allowing the shell to remain for tsvo days, I removed 

 it and sent the frog on its way rejoicing, a small hole 

 having been made where the shell was fastened. It 

 is certain that the shell became attached in the water, 

 and probably when the frog was quietly reposing on 

 the mud, as these animals bury themselves in the 

 mud, at all events during the day. Was the cyclas 

 hungry ? If the attachment was made to satiate its 

 appetite, was it not a daring attempt ? I should be 

 glad to know if any of the readers of Science- 

 Gossip ever witnessed such, and whether Cyclas 

 cornea is really carnivorous. — J. T. Niches. 



The Plague of Flies. — The common fly 

 {Musca domestica, &c.) has a strong dislike for the 

 musk-plant (Mimulus moscatus). If *' E. C. M. " 

 has boxes of this plant before the windows of the 

 rooms affected, the nuisance may be abated. — David 

 A. King. 



Parasites on Cyclops. — The vorticella-like 

 parasites "A. H. " mentions as occurring on cyclops 

 are probably epistyles. Of these, there are many 

 species, most of them branched, which Vorticella in 

 its adult stage never is. Some species — e.g., E. vege- 

 tis and E. grandis — are not branched, and almost 

 always occur on the minute crustaceans. The animal 

 might be podophrya, a suctorial infusorian, having 



a short stalk and head, covered with single, radiating, 

 cilia-like suckers. — David A. King. 



Wild Strawberries in January. — I think 

 the following fact is worth recording. Whilst out 

 for a walk with a friend last week (the third week in 

 January) on the borders of Wales, I gathered some 

 wild strawberries, about half the size of peas. They 

 \\ere green and in a healthy state, and the plants on 

 which they were growing were covered with flowers 

 and flower-buds. — H. G., Oswestry. 



YOLVOX globator in great profusion was found 

 by me in a pond near this town on 25th December, 

 1875. INIyriads of specimens were to be found there 

 throughout the following January, and then they dis- 

 appeared altogether. I have searched the pond many 

 times since, particularly in December last, and in the 

 present month of January, without finding a single 

 specimen. Owing to the heavy rain which has fallen 

 so continuously for several weeks past, the water has 

 been highly coloured with red marl, a condition 

 which may have been unfavourable to the develop- 

 ment of Volvox again this winter. — T. y. Scatter. 



Hawfinches. — With regard to the Hawfinch 

 breeding in this country : they are very common in 

 this part of Hertfordshire, but not much noticed on 

 account of their shyness. I have several times 

 reared the unfledged young ones, and repeatedly have 

 had the nests and eggs of the Hawfinch brought to 



me. 



-E.L. 



Insects and Plants. — Allow me to call the 

 attention of your readers to pp. 167-170, Letter IX, 

 in tlie seventh edition of Kirby and Spence's " Ento- 

 mology," 1856. There occurs the following : " Some 

 plants are gifted with the faculty of catching flies. 

 These vegetable muscicapce which have been enume- 

 rated by l3r. Barton, of Philadelphia {Philos. Mag., 

 xxxix. 107), may be divided into three classes : First, 

 those that entrap insects by the irritability of their 

 stamens, as Apocyniini androste mifolinm , Asclcpias 

 svrica and curassaoica, Neriiiin Oleander, and a 

 grass, Leersia lenticnlaris. The second class entrap 

 them by viscosity ; . . . . and the third by their leaves, 

 whether from irritability, as in Dionrea, Drosera, &c., 

 or from forming hollow vessels containing water, into 

 which the flies are enticed either by their carrion-like 

 odour, or the sweet fluid which many of them secrete 

 near the faux, as in Sarracenia, Nepenthes, Aquarium, 

 Cephalotus, &c. In this class may be placed the 

 common Dipsacus (Teazle), the connate leaves of 

 which form a basin, in which many insects are 

 drowned. To these a fourth class might be added of 

 those plants whose flowers smell like carrion (Stapelia). 

 Dr. Barton doubts whether the flowers can derive 

 any nutriment from the insects, and he does not think 

 the leaves of Dionxa, &c. can need any stimulus." 

 An experiment of "Mr. Knight's, nurseryman, in 

 King's Road, London," is then quoted, who "laid 

 fine filaments of raw beef" on the leaf of Dionsea, 

 which "was much more luxuriant than others not so 

 treated." .... " However problematical the agency 

 of insects as to their nutriment, there can be no 

 doubt that many species perform an important func- 

 tion with regard to the impregnation of plants, which, 

 without their aid, would, in some cases, never take 

 place at all." The Barberry, Iris, Asclepiadeos and 

 Orchidea;, Aristolochis, and Fig are then referred to. 

 Sprengel's then despised "Endecktes Geheimniss" 

 being quoted. " Sprengel asserts that, apparently to 

 prevent hybrid mixtures, insects will, during a whole 

 day, confine their visits to that species on which they 



