236 



NATURE 



[Jan. 9, 1890 



■gross anatomical investigation, minute histological examination, 

 and experimental inquiry were, in a striking manner, made to 

 assist each other, Dr. Gaskell, by tracing out the course and 

 determining the nature of vaso-constrictor and vaso-dilator 

 fibres, and comparing them with the cardiac augmentor and 

 inhibitory fibres, and with the fibres governing the visceral 

 muscles, has already reduced to order what previously was to a 

 large extent confusion, and has opened up what promises to be 

 the way to a complete understanding of the whole subject. 



The results arrived at, besides their great physiological im- 

 portance, on the one hand promise to be of great assistance in 

 ■practical medicine, and on the other are eminently suggestive 

 from a purely morphological point of view. 



The other Royal Medal has been awarded to Prof. Thomas 

 Edward Thorpe for his researches on fluorine compounds, and 

 his determination of the atomic weights of titanium and gold. 



Prof. Thomas Edward Thorpe's experimental work has 

 secured for him a place in the first rank of living experi- 

 mentalists. 



His researches, which are not confined to one department of 

 chemical science, but extend over many branches, are all distin- 

 guished both by accuracy and originality of treatment. As 

 examples of the high character of his investigations, those of the 

 determinations of the atomic weights of titanium and gold may 

 be specially cited as permanently settling the value of two most 

 important chemical constants ; whilst his researches on the 

 fluorine compounds, including the discovery of thiophosphoryl 

 fluoride, a body capable of existing undecomposed in the state 

 of gas, and his latest work on the vapour-density of hydro- 

 fluoric acid, do not fall short of the highest examples of 

 classical chemical investigation. 



The Davy Medal has been awarded to Dr. W. H. Perkin for 

 his researches on magnetic rotation in relation to chemical 

 constitution. 



Dr. Perkin is well known as the originator of what is now a 

 great industry, that of the coal-tar colours, by his preparation 

 and application to tinctorial purposes of a colouring matter 

 which had previously merely been noticed as affording a chemical 

 test for the presence of aniline. This, however, is now a long 

 lime ago, and it is for more recent work, the interest of which 

 is purely scientific, that the medal has been awarded to him. 



Dr, Perkin first showed, in 1884, that a definite relationship 

 exists between the chemical constitution of substances and their 

 power of rotating the plane of polarization of light when under 

 magnetic influence ; and he pointed out how the "molecular 

 coefficient of magnetic rotation" or " molecular rotatory 

 power " might be deduced. 



In 1884 he presented to the Chemical Society a lengthy paper 

 describing his method, and the results obtained for a very large 

 number of paraffinoid hydrocarbons and haloid and oxygenated 

 derivatives thereof; from these he deduced "constants," which 

 he has since shown to be applicable in calculating the magnetic 

 rotatory power of paraffinoid compounds generally. From time 

 to time_ he has published further instalments of his work, and 

 only quite recently has described the results obtained on examin- 

 ing nitrogen compounds, which exhibit many most interesting 

 peculiarities. 



The results are of special value on account of the exceptional 

 care devoted to the preparation of pure substances, and the 

 guarantee, which Dr. Perkin's reputation affords, that everything 

 possible has been done to secure accuracy ; and also because the 

 substances chosen are for the most part typical substances, or 

 belong to series in which a simple relationship exists. 



HAIL-STORMS IN NORTHERN INDIA. 



J N a paper recently published in the Journal of the Asiatic 

 Society of Bengal, Mr. S. A. Hill describes certain severe 

 hail-storms and tornadoes that occurred on April 30 and May i, 

 1 888, in the Gangetic doab and Rohilkand in Northern India. ^ 

 Tornadoes are not very common in India, but they appear to 

 have been somewhat more prevalent than usual in the spring of 

 1888, the storms in question having been preceded on April 7 

 by a very destructive tornado at Dacca in Bengal, a full descrip- 

 tion of which was given by Mr. Pedler and Dr. Crombie in a 

 previous number of the Society's Journal. Like all previously 

 recorded storms of this character, these occurred in the spring, 



' Op. cit., vol. Iviii., Part 2, No. 2, 1889. 



when the seat of minimum pressure is established in the Lower 

 Punjab, and a trough of low pressure extends from this region 

 eastward to the Gangetic plain. To the south of this trough very 

 dry west winds, the hot winds of Northern India, prevailed in 

 Rajputana and Central India, while, to the north of it, damp 

 easterly winds blew up the northern margin of the plain and 

 across the outer slopes of the Himalaya. It is apparently in the 

 meeting of these two winds, where the former blows in an upper, 

 the latter in the lower, stratum, that are generated the thunder 

 squalls that form a normal feature of the spring months in 

 Northern India ; and tornadoes, as Prof. Ferrel has shown, are 

 merely an exaggerated development of the thunder squall. In 

 the present instance, ordinary storms of this character, and dust 

 storms, occurred pretty generally over all the north-western 

 districts of the North- West Provinces, simultaneously with the 

 tornadoes in Rohilkand and the Gangetic doab. 



From the evidence quoted by Mr. Hill, it does not appear 

 indeed to be positively established that any of the storms described 

 exhibited all the characteristic features of tornadoes, as was un- 

 doubtedly the case of the Dacca storm. No mention is made in 

 any of the reports of any whirling column having been actually 

 observed ; and that whirlwinds were the real agents of destruction 

 seems to be inferred chiefly from the destructive force of the 

 wind, especially its lifting power, and some rather vague reports 

 on the wind's changes during the passage of the storm. On a 

 point of this kind, however, in India, negative evidence goes for 

 little, and the chief subject discussed in Mr. Hill's paper, viz. 

 the conditions which determine these atmospheric disturbances, 

 is of equal interest, whether they were really tornadoes or only 

 remarkably severe hail-storms of the more usual kind. 



In the barometric changes of the days preceding the storms 

 there does not appear to be anything that throws much light on 

 their genesis. The relative distribution of pressure shown by the 

 observations on the Indo-Gangetic plain underwent but little 

 variation, and the existence of a slight secondary depression in 

 the immediate neighbourhood of the storm tract, on April 30, is 

 inferred solely on the evidence of two Himalayan stations at 

 elevations of 5300 feet and 6000 feet above the sea, and may be 

 delusive. There had, however, been a general steady fall of the 

 barometer for three days before the storms of April 30 — one of 

 those oscillations, apparently, which Mr. Abercromby has termed 

 surges, and a rapid rise set in after the storms. As has been 

 pointed out elsewhere, this is an ordinary recurrent feature of 

 the season. 



It is in the changes in the vertical distribution of temperature 

 that Mr. Plill finds the conditions that determined the atmo- 

 spheric disturbance. Taking as his fundamental data the observed 

 temperatures of the three stations, Roorkee at 886 feet, Dehra 

 at 2233 feet, and Mussooree at 6881 feet, and assuming that 

 these represent approximately the rate of vertical decrease over 

 the neighbouring plain, he computes the fall of temperature for 

 increments of 1000 feet up to 10,000 feet by means of a simple 

 formula of interpolation, and finds that, up to the forenoon of 

 April 30, the condition of unstable equilibrium which results 

 from the diurnal heating of the plains did not extend beyond 

 3000 or 4000 feet above the ground surface. This would set up 

 a considerable amount of convective interchange between these 

 lower strata, but the cloud-forming strata would still be in a 

 stable condition, at least in a non-saturated atmosphere. On 

 the afternoon of April 30, the conditions were changed. With a 

 great fall of temperature at the lowest and highest stations, as 

 compared with the previous day at the same hour, that of the 

 intermediate station was but little affected, and hence the com- 

 puted table shows a reduction of the vertical decrement at low 

 levels, a corresponding increase at the higher levels, and a 

 transfer of the condition of unstable equilibrium from the former 

 to the latter. Simultaneously with this change took place that 

 violent disturbance of the atmosphere that resulted in the hail- 

 storms on the plains. 



Mr. Hill's conclusions are entirely in accord with what might 

 be expected on a priori grounds. But before they can be fully 

 accepted, it is necessary to scrutinize the data, and as the result 

 of this scrutiny we must confess they do not seem to us com- 

 pletely convincing. We may put aside the question whether 

 and to what extent the empirical formula of interpolation 

 adopted by Mr. Hill really expresses the law of decrement of 

 temperature, since, although it would evidently fail for extrapola- 

 tion much beyond the altitude of 7000 feet, it probably does not 

 involve any very serious error below that limit, provided the 

 numerical values afforded by observation are trustworthy. The 



