SCIENCE- GOSSIP. 



far from being straight lines. These were com- 

 pared with the magnetisation curves obtained in 

 the usual manner. Mr. Barlow's result has an 

 important bearing upon the theory of electro- 

 magnetism, for it shows conclusively that change 

 of magnetic resistance is not proportional to 

 the square of the magnetisation. He obtained 

 the empirical formula &<p = aV 4- bV + el 6 . The 

 hysteresis curves plotted by Mr. Barlow are entirely 

 new, and present many beautiful symmetrical 

 figures. 



Colour op the Sky. — Professor J. M. Pernter 

 has contributed a paper to the Vienna Academy of 

 Sciences on the polarisation of light in turbid 

 media, considered with reference to the colour of 

 the sky. He finds a very close agreement between 

 the two phenomena, and thus confirms experi- 

 mentally Lord Rayleigh's theory of the colour of 

 the sky. 



Hailstorm Artillery. — The study of hail and 

 thunder storms is receiving considerable attention 

 in Italy and Austria. In Italy several stations 

 have been organised for the purpose of experi- 

 menting as to the possibility of dispersing thunder- 

 clouds by gun-firing. In response to the enthusiasm 

 of Italian agriculturists in the matter, the Govern- 

 ment has voted a sum of money for the establish- 

 ment of two shooting stations in suitable localities, 

 and has provided them with the most sensitive 

 instruments for predicting the advance of storms. 

 In some cases the firing appears to have had a 

 favourable effect, while in others the firing 

 apparatus was choked by the falling hail. Mr. 

 W. N. Shaw states in " Nature" that the practice 

 of firing off gunpowder to protect vineyards from 

 hail is spreading in Austria. Cylindrical mortars, 

 provided with conical mouthpieces, are used for 

 the purpose. The vortex rings discharged from 

 the large mortars have been found to reach a 

 height of 400 metres only, which is considerably 

 short of the level generally occupied by the storm- 

 clouds. This seems to show that the vortex rings 

 would hardly ever reach the clouds, so that until 

 more powerful apparatus is employed the results 

 can rarely be satisfactory. 



Experiments with Human Subjects.— The 

 determination of the efficiency of a man during a 

 six days' bicycle race in France has an interesting 

 bearing on the question as to whether organic life 

 is subject to the second law of thermodynamics 

 or whether Maxwell's "demons" actually exist in 

 the animal kingdom. The " Journal de Physique " 

 gives a lucid account of experiments upon the 

 " Thermal Conductivity of the Human Skin," by 

 J. Lefevre. The author made absolute determina- 

 tions of the thermal conductivity of the skin 

 of a human subject by calculating the coefficient 

 of heat emission from the external surface, the co- 

 efficient of heat transmission through the skin, and 

 the coefficient of the heat restoration on the inner 

 surface of the skin. The subject was immersed 

 always to the same depth in water at different 

 temperatures. The skin area in contact with the 

 water was estimated with the aid of a tightly 

 fitting garment. The external skin temperature 

 was estimated with the help of a thermocouple, and 

 also the inner temperature was found by inserting 

 a needle-shaped thermocouple into the skin, the 

 thickness of the skin varying from 1-5 to 2 mm. 

 The coefficient of conductivity is found to be of the 

 order of that of guttapercha. 



FIELD BOTANY. 



CONDUCTED BY JAMES SAUNDERS, A.L.S. 



Surrey Plants in 1901.— Early in March 

 Galanthus nivalis and Eranthis hyemalis were in 

 flower on Headley Heath — the snowdrop with 

 double flowers, being presumably of garden origin, 

 and the winter aconite probably so. Melleborus 

 foetidus was seen at its old locality at Headley 

 Lane, and H. viridis was found between Chipstead 

 and Tadworth, the latter locality being one of four 

 fresh localities in which the green hellebore has 

 been met with in Surrey. Between Chipstead and 

 Tadworth grow the white-flowered form, leneantha, 

 of Viola silvestris ; also Luzula maxima, a re- 

 putedly rare plant in Surrey, but the great wood- 

 rush is found in at least five widely-separated 

 localities in the county. In May Trigonella was 

 flowering on Mitcham Common. Here I was un- 

 successful, in finding Ranwneuhts parvifloms, which 

 the preceding year was growing sparingly on a 

 grass-grown bank. Mitcham Common is an old- 

 recorded locality for this species. During June a 

 walk on the hills north of Oxted was rewarded in 

 seeing nine of the British orchids, and later in the 

 month ten species of these plants were observed in 

 the neighbourhood of Horsley. Other interesting 

 plants of the country south-west of Horsley are, 

 Arenaria tennifolia, Polygald oxyptera, Valeriana 

 mihanii, Orobanelie elatior, and the early summer 

 flowering variety (praecox) of Gentiana amarella. 

 Pilularia globitlifera has been exterminated at 

 Holmwood Common, and also, apparently, at 

 Earlswood Common. It is, therefore, satisfactory 

 to be able to mention that the pill-wort grows in 

 the neighbourhood of Ockham so abundantly as 

 would seem to defy the fate that has befallen it 

 elsewhere. In this same district grow Damasonium 

 stellatwn, Juncus diffusus, lycopodium inwndatiim, 

 two sundews, Littorella, etc. On Epsom Common 

 in August were seen in flower the duckweed Lemna 

 gibba and Erythraea pulchella. In this neighbour- 

 hood two more localities for Pilularia were met 

 with. A plant that has not been recorded in recent 

 times for the county is the viscid groundsel, Seneeio 

 viscosus. It grows at West Dulwich, where I have 

 seen it during the past ten years. When in the 

 neighbourhood of Dorking, I encountered two such 

 local plants as Puliearia vulgaris and the variety 

 pseudo-botryoides of Chenopodiwn rubrvm. — C. E. 

 Britton, 35 Bugdale Street, Camberwell, London, 

 S.E. 



Mycetozoa of Switzerland. — It is desired by 

 some of the leading Swiss botanists to publish a 

 list of all the species of the mycetozoa that have 

 been recorded for that country. Up to the present 

 time only forty-six forms can be catalogued, 

 although of course many examples of the commoner 

 kinds have been found. It is probable that per- 

 sistent search in damp woods, especially in the 

 early autumn, would speedily double the number 



