Fl.HKLARV. 191. 



KNOW Li;i)Gl 



material of which to make a specific gravity bottle, or 

 pyknometer. A pykiiometer is a small tube drawn out to a 

 tube of fine bore at each end ; one of these fine tubes is bent 

 round so as to form a U tube, with the tube of larfjer bore as 

 one of the limbs of the U. The apparatus is weighed, full of 

 water np to a certain mark on the small tubes, and also full of 

 a li(iuid of which it is required to find the density. From the 

 two weighings a measure of the density of the liquid is obtained, 

 pro\ided proper precautions are taken for observing the 

 temperature. When using a glass pyknometer it is often 

 necessary to take account of the expansion of the glass itself, 

 but with a silica pyknometer this is not necessary ; while the 

 latter are much easier to clean and dry, because they can be 

 heated strongly without fear of cracking. 



Silica is an excellent insulating material for electrical instru- 

 ments. Glass adsorbes water on its surface ; this water 

 dissolves the silicates of the glass, and forms a conducting 

 layer on the surface of the glass ; unless \ery dry glass is a 

 poor conductor, but silica has not got this defect. 



Professor Strutt some years ago constructed a tube of silica 

 in which to measure the electrical conductivity of mercury at 

 high temperatures. The quartz tube was the shape of an 

 inverted Y. The tube was nearly completely filled with 

 mercury. Wires led into the two limbs of the Y tube, and 

 were sealed in with wax. The junction of the limbs of the Y 

 was strongly heated. .At a red heat the resistance of the 

 mercury was about doubled. Mercury boils under atmospheric 

 pressure at 356" -7 C. By heating it in a closed quartz tube of 

 the above description it was possible to keep it in the liquid 

 form well above this temperature, and thus obtain red-hot 

 mercury. It was not possible, without bursting the tube, to 

 reach the critical point, at which temperature the mercury 

 would go over from the liquid to the gaseous condition, and 

 above which it would not be possible to obtain liquid mercury. 

 It appears, though, from the experiments that the electrical 

 resistance of liquid mercury would be the same as that of the 

 mercury vapour at the critical point. 



ZOOLOGY. 



By Professor J. .-Vrthur Thomson. M..A. 



IS LEFT - H.\NDEDNESS HEREDIT.AKY :- — This 

 question has been recently studied by Professor H. E. Jordan. 

 The cause of left-handedness remains obscure, though it may 

 be regarded as a congenital asymmetry such as is common in 

 organisms. There is much to be said for Sir D. Wilson's con- 

 clusion that left-haudedness is associated with a greater 

 development (preponderant size and weight) of the right 

 cerebral liemisphere. .As we ha\e previously remarked in 

 these Notes, the percentage occurrence in various races is not 

 known with any accuracy. The anatomist Hyrtl puts it at 

 two per cent, among the civilised races of Europe, which is not 

 far oft" what it was long ago among the warriors of the tribe of 

 Benjamin. It is important to distinguish between structural 

 asymmetry (difference in size and weight), and functional 

 iiie<iuality (dift'erence in deftnessl. It is not less important to 

 try to distinguish between a constitutional tendency and the 

 result of education. Thus most parrots receive with the left 

 foot, but that is because they are ordinarily approached in feed- 

 ing with the right hand. When the left hand is consistently 

 employed in the feeding, the parrot responds with its 

 right foot. Jordan has investigated seventy-eight hneages 

 in which left-handedness was noted in a survey of 

 about three thousand individuals, and his facts go to 

 show that left-handedness is hereditary. But they do not 

 throw any light on the mode of the inheritance. Left- 

 handedness does not even appear to follow Mendelian principles 

 of inheritance, but the data are somewhat limited. So far as 

 they go they merely yield the conclusion that left-handedness 

 is in some way hereditary. 



I NTEK -SPECIFIC AND I N T K A -S P E C I F I C 

 STRUGGLE FOR EXISTENCE.— In a report on a recent 

 visit to Cavilli Island, one of the Philippines. Mr. Dean C. 

 Worcester has the following vivid passage which well 

 illustrates the struggle for existence between antagonistic 



species, and also, in a way, the struggle for existence between 

 members of the same species. The actors were the red- 

 legged boobies [Siila piscator), related to our gannet, and the 

 frigate birds (Frciiata aquila). "Just before dusk, as we 

 were leaving for the steamer, we witnessed an extraordinary 

 scene. Large numbers of red'legged boobies which had 

 apparently been fishing all day, began to return, bringing fish 

 to their nesting mates and to their young. The frigate birds 

 promptly formed a skirmishing line and, singly or in pairs, 

 attacked all comers, compelling them to give up their fish. 

 Some of the boobies, possibly sophisticated individuals which 

 had learned wisdom by experience, actually handed their fish 

 over to the frigate birds and so escaped without much 

 drubbing, but less experienced or more obstinate individuals, 

 which at first refused to disgorge, were vigorously punished 

 until they changed their minds and threw up their fish which 

 were most adroitly caught in the air by their piratical enemies. 

 In one instance, two frigate birds set upon a booby, one of 

 them attacking him from above, and the other flying below to 

 catch the fish which he dropped, and getting five out of seven. 

 Soon the incoming boobies began to arrive in flocks, and the 

 frigate birds were not able to set upon them all, so that many 

 individuals got through to the island. Once among the trees 

 they were left in peace." 



WARNING COLOUR IN A CHAMELEON. — Cyril 

 Crossland records the fact that a chameleon can frighten a 

 dog by its rapid change of colour. It was a fox terrier's 

 attack that he watched. The chameleon tried to run away, 

 but it is not good at that 1 " In a few seconds the impossibility 

 of escape seemed to reach the animal's brain, when it at once 

 turned round and opened its great pink mouth in the face of the 

 advancing foe, at the same time rapidly changing colour, 

 becoming almost black. This ruse succeeded every time, the 

 dog turning oft" at once." In natural leafy conditions the 

 startling eftect would be much greater, — a sudden throwing off 

 of the mantle of invisibility and the exposure of a conspicuous 

 black body with a large red mouth. 



LIFE OF TISSUES REMOVED FROM THE BODY.— 

 Everyone knows that a piece of a branch or a piece of a potato- 

 tuber will remain alive for a considerable time after it is cut 

 off", that posts of wood driven into the ground sometimes burst 

 into leaf, that a small fragment of many a plant, from liver- 

 wort to begonia, may grow into an entire plant. Similarly, 

 among animals, the excised heart of a turtle, in appropriate 

 conditions, will continue beating for several days after the 

 bulk of the animal has been made into soup, and has passed 

 into a new incarnation. A fragment of sponge, of hydroid, of 

 sea-anemone, of certain worms, and so forth, can regrow the 

 whole. We should like to have more information in regard 

 to the limits of these experiments. In the case of Hydra it 

 has been found that the regenerating fragment must not be 

 very small (a quantitative limit) and that it must contain 

 samples of the different kinds of cells in the body (a qualita- 

 tive limit). Professor H. V. Wilson has recently shown in 

 regard to some sponges that they may be minced and strained 

 through a cloth strainer, — and yet the debris poured out in an 

 appropriate place will develop into a proper sponge. Of late, 

 too, interesting experiments have been made in keeping pieces 

 of tissue alive in suitable media outside the body. What 

 happens in most cases is that they flourish for a time (three 

 to fifteen days) and then cease growing and die. It has been 

 suggested, however, that the death may be rather contingent 

 than necessary. It may be due to the accumulation of waste- 

 products. So Alexis Carrel has devised a system of artificial 

 rejuvenescence, washing the tissue from time to time with 

 " Ringer's solution," and placing it in a medium of plasma 

 and distilled water. .\ piece of connective tissue revived nine 

 times — staving off senescence and death, and was growing 

 actively thirty-four days after its removal from the body. 



FOSSIL WASPS' NESTS.— The geological record, whose 

 imperfections are so often proclaimed, has also its surprises. 

 We have just been reading a description given by Professor 

 .Anton Handlirsch of some hazel-nut-like bodies from the upper 

 Oligocene of Florsheim. They occurred along with snails' 



