250 



NATURE 



\July 12, 1888 



are distinctly subject to climatic causes, and the explana- 

 tion given in my former article, which attributes them to 

 irritability of temper consequent on long-continued heat 

 and moisture, is the best I can put forward. 



When the birth statistics are analyzed with reference to 

 the annual period, results equally striking and curious are 

 brought out. The numbers registered, when tabulated 

 month by month, corrected for the causes of error 

 mentioned at the commencement of this article, and 

 thrown into the form of average rates per thousand per 

 annum, give the following table, in which also the 

 monthly ratios, which are for nine years only, have been 

 slightly altered so as to make the annual mean equal to 

 that already found for ten years : — 



Year 



22-28 



45'40 



io3'77 



From the existence of the Holi festival among the 

 Hindus, and of similar spring festivals, accompanied 

 with lascivious songs and dances, among many bar- 

 barous tribes, as well as from the traces of such festivals 

 still surviving in Europe, and the hints given by classical 

 writers regarding the nature of certain annual religious 

 mysteries performed by the early Greeks and Romans, 

 anthropologists have thought that possibly, during pre- 

 historic times, the human species, like the lower animals 

 in a state of nature, had an annual pairing-time. If any 

 traces of such a condition still survive, we may with some 

 confidence look for them in India, where a large number 

 of the poorer classes are chronically on the verge of star- 

 vation, and the different seasons are sufficiently marked 

 in character to affect people differently both in body and 

 in mind. The birth-rates in the above table, represented 

 by Fig. 17 in the diagram, exhibit a most distinct annual 

 variation, smoother and more uniform in character than 

 any of the mortality curves, and with a range equal to 

 nearly 50 per cent, of the mean value. The minimum 

 falls in June and the maximum in September, — dates 

 which point to a maximum of conceptions in December, 

 and a minimum in September. The latter month is near 

 the end of the long and depressing hot season, when 

 malarial influences are rapidly increasing to a maximum, 

 the food-supply of the year is nearly exhausted, and there 

 is the greatest tendency to suicide. The births, as well 

 as the deaths, therefore, show that at the end of the 

 rains the vitality and energy of the people have reached 

 low-water mark. 



In December, on the other hand, not only is the 

 salubrity of the country greatly increased, as shown by 

 the rapid diminution of nearly every cause of death, but 

 food is again cheap and abundant. The crops of millet, 

 on which the poorer classes live, are sown in July and 

 reaped in November. During December and the latter 

 half of November they are threshed out, and then is the 

 season for paying the village functionaries and labourers 

 their share of the produce. Consequently food is more 

 abundant at this time of the year than at any other, and 

 as a result of these conditions we find a large number of 

 births the following September and October. 



It thus appears that among the poorest of the popula- 

 tion there is probably still a more or less distinct annual 



reproductive season, but instead of being determined by 

 the returning warmth of spring, as must have been the 

 case in prehistoric Europe, it follows the annual return of 

 healthy conditions with abundant food-supply. That the 

 Holi festival occurs in spring, instead of in December, is 

 perhaps to be accounted for as a survival from a time 

 when the ancestors of the Hindus lived in a colder 

 climate. 



In the last column of the table are given the monthly 

 values of the ratio of males to females at birth. This 

 appears to be subject to a small but distinct annual 

 variation, with a maximum in July, and a minimum in 

 December ; but whether this is a remote and obscure 

 physiological effect of the annual march of the seasons, 

 or only a chance arithmetical result, I cannot say. 



Allahabad, February 8. S. A. Hill. 



ON THE ORBITS OF AEROLITES} 



MY studies have led me to the following three 

 propositions : 



1. The meteorites which we have in our cabinets and 

 which were seen to fall were originally fas a class, and 

 with a very small number of exceptions), moving about 

 the sun in orbits that had inclinations less than 90 ; that 

 is, their motions were direct, not retrograde. 



2. The reason why we have only this class of stones in 

 our collections is not one wholly or even mainly depen- 

 dent on the habits of men ; nor on the times when men 

 are out of doors ; nor on the places where men live ; nor 

 on any other principle of selection acting at or after the 

 arrival of the stones at the ground. Either the stones 

 which are moving in the solar system across the earth's 

 orbit move in general in direct orbits ; or else for some 

 reason the stones which move in retrograde orbits do not 

 in general come through the air to the ground in solid 

 form. 



3. The perihelion distances of nearly all the orbits in 

 which these stones moved were not less than 0-5 nor 

 more than ro, the earth's radius vector being unity. 



The first and thirds propositions are limited strictly by 

 their terms to the meteorites from stone-falls actually 

 witnessed, and also represented by specimens in some one 

 or more of existing collections. The investigations that 

 have led to them have been limited to the same stone- 

 falls. This is not because any line of separation is sus- 

 pected to exist astronomically between the stone-furnishing 

 and detonating meteors, or even between them and the 

 shooting stars, but because, for manifest reasons, any facts 

 established about these stones have a greater value than 

 similar facts about meteors from which no stones have 

 been secured. 



About 265 observed falls are represented by specimens 

 in existing collections. The history of these falls I have 

 searched out with no little pains, so far as the material 

 for such history could be found in books accessible to me. 

 Every direct statement and every indirect indication 

 which I have obtained about the paths of these meteors 

 through the air have been carefully considered, and their 

 meaning and value duly estimated. The determination 

 of the path of a stone-furnishing meteor through the air 

 is greatly aided by the fact that we know at once one 

 point of the trajectory, viz.: the point where the stone 

 strikes the ground. To this fact may usually be added 

 another, viz.: that some of the observations are by 

 persons near the place of fall, and hence their statements 

 of direction, so far as we may trust them, have peculiar 

 significance. In individual cases it will be found that not 

 much reliance can be placed upon the asserted direction 

 of the meteor's motion. But when the results are all 



1 " Upon the relation which the former Orbits of those Meteorites that are 

 in our colltctions, and that were seen to fall, had to the Earth's Orb.t" by 

 H. A. Newton. (From the American Journal of Science, July 18S8.) 



