2 14 



HARD WICKE'S SCIENCE- G OSSIP. 



victims to the old gardener or keeper — thus some- 

 what discrediting the theory that impressions strongly 

 implanted on the brain of a parent are transmitted ; 

 so as to act without supplementary teaching — the 

 instinct of swallows for example. — F. F. 



Tea Stains. — If a strong decoction of tea is added 

 to a solution of iron sulphate, a black coloration is 

 immediately given. It is formed owing to the action 

 of an organic astringent acid present in tea, and is 

 very analogous to the formation of ink, by mixing 

 together tincture of galls, and sulphate of iron. 

 Attempts have been made to utilise spent tea-leaves 

 for a like purpose. — C. j. IV. 



Tea Stains. — Dry tea-leaves contain from thirteen 

 to eighteen per cent, of an astringent principle, which 

 is a modification of tannin. This, in contact with iron, 

 produces a blackish-blue precipitate, in fact, a kind 

 of ink.— IV. M. Hohnes. 



Tea Stains. — Most teas contain tannic acid in 

 greater or less quantity, and when tannic acid comes 

 in contact with steel, tannate of iron is formed, which 

 is of a bluish-black colour. Tannate of iron is of 

 course the colouring material of ordinary black ink. 

 R. N. B. will find ample information on tannic acid in 

 any work on organic chemistry. — Rev. S. D. Tit mas, 

 Godalming. 



Under what circumstances is the Yew 

 Poisonous to Horses and Cows ? — Youatt states 

 in his work on "Cattle" on the authority of M. 

 Husard, that "in Hanover and Hesse cattle are 

 partly fed upon leaves of the yew. The quantity of 

 yew is small at first, but it is gradually increased 

 until it constitutes the greater part of the food. The 

 inhabitants of Hanover and Hesse are nevertheless 

 perfectly aware of the poisonous properties of the 

 leaves of this tree, and are sometimes taught, by dear 

 experience, that it will destroy their cattle, unless it 

 is managed with this degree of caution." The 

 poisonous properties are due to a substance called 

 "taxine," which has not yet, as far as I am aware, 

 been thoroughly examined. Most! authorities have 

 agreed that yew leaves in all conditions are poisonous 

 both to man and cattle ; and it would not be difficult 

 to furnish overwhelming proof of this. Is your cor- 

 respondent J. H. G. quite sure that the van-horses 

 ate any of the yew from the garden ? If not, the fact 

 that thev have never suffered, may be easily accounted 

 for.— IV. M. Hohnes. 



Cossus at Sugar. — -With reference to this subject 

 I may mention a similar instance of this insect coming 

 to sugar some two seasons ago ; when going on to 

 the field rather later than usual, and not considering 

 it agood locality, I put the mixture on rather sparingly, 

 so this individual must have been possessed of very 

 keen senses. It was a fine female, and came on at 

 about dusk, almost before anything else. Is there any 

 satisfactory reason why the Nocturni so seldom seem 

 attracted by the sugar ? If any of your correspondents 

 could suggest such, I should be glad to receive the 

 information. — A. Horsley Hinton. 



Cossus on Sugar. — While sugaring with a friend 

 in Highgate Woods in the summer of 1S76, I was 

 surprised to find a fine male specimen of cossus, 

 seated on the higher part of the "sugar streak," 

 evidently enjoying his unexpected luxury. My friend 

 succeeded in capturing him, and now has him in his 

 collection. On mentioning this capture to another 

 entomologist in the wood, I was told that they are to 

 be caught by sugaring on the willows on the banks of 

 the Lea in Essex. — J. 0. B. 



Leaves of Rhubarb. — I learn from H. G. Glass- 

 poole's interesting paper on "The History of 

 Rhubarb," that the leaves of that plant were formerly 

 eaten as a vegetable. Will one of the readers of 

 Science-Gossip kindly tell me of a good mode of 

 preparing and cooking them as such ? — A. M. P. 



Notes of Frogs. — We have been passing the 

 winter at Biarritz, and often in our walks in the 

 neighbourhood we have heard a noise like the 

 tinkling of many sheep bells. This noise, some people 

 told us, was produced by a toad, and others by a 

 frog ; as both these reptiles abounded in the hedges, 

 it was difficult to ascertain from which the noise 

 really proceeded. Can any reader of the Science- 

 Gossip inform us if the pretty, cheerful sound was 

 made by a frog, or a toad, and how the noise was 

 produced ? — V. G. 



Indigenous Medicinal Plants. — I should be 

 grateful for any information regarding localities 

 of the Indigenous Medicinal Plants, in the ancient 

 district Cumbria ; for identification only, none will 

 be removed. — y. Foster. 



Stock-Ice. — In Science-Gossip for June a corre- 

 spondent states that in certain frosts the bottom of 

 streams and "broads" in Norfolk will freeze, and at 

 the giving of the frost a substance something like ice- 

 cream in appearance will come to the surface, to which 

 the local name of "Stock-Ice" is given. During a 

 severe winter which I spent many years ago in 

 Germany, I observed the phenomenon of water be- 

 ginning to freeze at the bottom instead of the top — 

 this occurred in one of the mountain-streams flowing 

 into the Neckar. I have not witnessed it since, nor 

 have I met with any explanation or mention of it, 

 but I thought at the time, and have since assumed, 

 that I had hit upon the true solution. Water, when, 

 in a state of agitation, does not freeze so readily as 

 when it is still. The stream at its surface was in rapid 

 motion, but at the bottom there were recesses where the 

 water was nearly, if not entirely quiescent. Here, as 

 the temperature of all the water, and the containing 

 channel was far below the freezing-point, crystallisa- 

 tion was able to begin. The process was possibly 

 assisted by the presence of objects serving as a nucleus, 

 but I did not observe this, nor am I aware whether 

 the formation of ice is promoted by such means, but 

 the ice remained at the bottom in flocculent masses, 

 and may have been attached to the channel by some- 

 thing round which it had formed. I should add that 

 lower down the valley an overshot mill was completely 

 draped with curtains of icicle, which had accumulated 

 till the wheel was completely stopped. It may be 

 said that there the water, though in motion, had 

 frozen. I imagine, however, that where water is 

 already below 32 Fahr., and is only kept from freez- 

 ing by motion, some very slight change of conditions 

 is sufficient to turn the scale and to cause the process 

 of crystallisation to set in. I shall be glad if some of 

 your scientific readers will give their views on the 

 facts stated, and my suggested explanation of them. — 

 y. Hannen, Off/mm, Lewes. 



Dutch Clover. — In our neighbourhood, Cleve- 

 don, Somerset, I find this year an abundance of the 

 Dutch clover (T. repens), with flower heads in 

 various stages of transformation or reversion to leaves. 

 The petals, and sometimes the carpels, are quite 

 green and trifoliate shaped, exactly like miniature 

 specimens of the ordinary leaves. Trifolhun kybridum 

 shows the same tendency to monstrous growth this 

 year. The excessive rainfall is suggested as a cause. 

 — W.E. Green. 



