NA TURE 



[October lo, 1907 



that he has not been entrapped by the advertisement 

 of a new patent remedy. Mr. Horner appears to be 

 entitled to the credit of having arrived twenty-five 

 years ago at the now fashionable doctrine that man is 

 essentially a behaving animal — or, as he e.Kpresses it, 

 that " man's life is made up simply of a series of 

 acts " — and of having anticipated the Pragmatists in 

 the deduction " that acts form the only proper basis 

 of philosophy." Unfortunately, he has shown in 

 these pages no competence to construct upon this basis 

 anything with which, even in these hard times, philo- 

 sophy should be asked to allow her name to be con- 

 nected: 



The More Important Insects Injurious to Indian Agri- 

 culture. Memoirs of the Department of Agriculture 

 in India, vol. i.. No. 2, Ento. Se. Pp. 139 + v; 80 

 figures. By H. Maxwell-Lefroy. (Pusa : Agricul- 

 tural Research Institute, 1907.) Price Rs. 3. 

 The above-named paper is a very excellent foundation 

 for the young economic entomologist in India to work 

 upon. The chief insects known to be injurious to 

 crops in India are briefly described in systematic order. 

 The method of treatment of this subject is novel, 

 and might well be copied by others compiling similar 

 lists. 



The technical name of each pest is given, and then 

 one or two references of interest and a short, concise 

 description of the insect follows. Short notes of the 

 distribution, biology and food plants are appended, 

 and finally the writer's opinion as to the status of the 

 insect as a pest. A large number of the adults are 

 figured, and in a few instances the larvae also. 



Showing the backward state of economic entomologv 

 in India is the fact that only four aphides are placed 

 in this list. A sound foundation is, however, being 

 laid, and we are glad to learn that a supplementarv 

 list is to follow when the material is available. In all 

 131 pests are dealt with, some of which are well known 

 in Europe, such as the diamond-back moth, the turnip 

 moth (Agrotis segetis), the large cabbage white, con- 

 volvulus hawk moth, the corn aphis, cabbage aphis, 

 and thistle aphis. F. V. T. 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for opinions 



expressed by his correspondents. Neither can he undertake 



to return, or to correspond with the writers of, rejected 



manuscripts intended for this or any other part of Nature. 



No notice is tahen of anonymous commtinications.] 

 The "Friar's Heel" or "Sun Stone." 



In an old number of Notes and Queries (4, v. 598) 

 E. Dunkin asks " why the ' Friar's Heel ' at Stonehenge 

 is so named," and the only answer I can find in the 

 bibliography of Stonehenge (Wilts Archaeological Maga- 

 zine, vol. xxxii.) is as follows : — " It may have been called 

 the Heel stone," observes Prof. Flinders Petrie, "from 

 A.S. helan, to hide or conceal, just as a cromlech at 

 Portisham, Dorset, is called the ' Hel-stone.' " 



The word Heal or Hele is used in N. Wiltshire in 

 this sense. " When the ground is dry and hard and the 

 wheat when sown does not sink in and get covered up at 

 once, it is said not to heal well " (Dartnell and Goddard, 

 " Glossary of Wiltshire Words," 1893), but this mean- 

 ing is more applicable to the cromlech than to the upright 

 stone at Stonehenge. 



Modern researches as to the date of the erection at 

 Stonehenge point to a time when a Celtic word rather than 

 an .A.S. word would have been in use, and it has occurred 

 to me that the word Hcol, which is the Breton word for 

 the .'iiin, may be an explanation of the name of the 

 stone in question, as it is the stone used for the observ- 

 ation of the rising sun at Midsummer. It would be 

 NO. 1980, VOL. 76] 



interesting to learn from Celtic scholars what equivalent 

 Celtic word was in use in Britain when Hvol was the 

 word used in Brittany, and whether Heol or Hel would 

 be the Cornish form of the Welsh word for the sun. The 

 Rev. J. Griffith tells me " that haul is the oldest Welsh 

 form of the word — then hcil, and now in literary Welsh 

 haul. " 



The foolish mcdia-val legend of the devil flinging the 

 stone at a mocking friar and hitting him on the heel is 

 evidently of very late date, but it is singular that a similar 

 legend is attached to the " Hel Stone " in Dorsetshire, 

 where the story is that the devil, playing at quoits in the 

 island of Portland, flung the Hel Stone across to 

 Portisham (see Hutcbings' " Dorset," i., 554). 



There is another Hel Stone near, so called in common 

 with the cromlech at Portisham, and it stands in a small 

 combe to the north of Long Bredy hut ; it is a rude mass 

 about 7 feet high and 7 feet wide, whilst the capstone of 

 the cromlech at Portisham is 10 feet by 7 feet by 2J feet 

 (Warne's "Ancient Dorset," pp. 111-13,1). 



By the time the legends of the " Friar's Heel " and 

 Hel .Stone were invented, the old language would have 

 been a thing of the past, but possibly the old name 

 lingered in the memory of men wholly ignorant of its 

 significance, giving rise to the traditions. 



October 4. T. Story Maskelvne. 



The Double Drift Theory of Star Motions. 



Prof. J. C. Ciiamberlin's planctismal hypothesis has 

 given geologists a great deal of matter for thought, and 

 on the whole the phenomena with which they are 

 acquainted appear to fall into line when the earth is con- 

 sidered as a body that has always been solid. The 

 cosmical aspect of the question, which Prof. Chamberlin 

 introduced in advancing his hypothesis, geologists are 

 unable to judge, and they are waiting until astronomers 

 give them an opinion before adopting the hypothesis on 

 the larger scale. On the planetismal hypothesis our 

 stellar system is a disc the edge of which is the Milky 

 Way ; beyond lies another stellar system, the so-called 

 nebula in Andromeda, for all the most distant stars in 

 the neighbourhood of the nebula appear to be this side 

 of the luminous disc. If our stellar system is of the same 

 nature as that of the nebula in Andromeda, then it must 

 be a spiral nebula with two equivalent arms originating 

 from a central core and winding spirally round the centre 

 in approximately the same plane. Suppose our sun had 

 experienced a gravitational drag and was moving at a 

 less rate than the general average of the other stars, or 

 suppose its spiral course was steeper than the general 

 average, and hence its angular velocity less, then an 

 observer regarding the rest of our stellar system from our 

 planet would see the stars near the centre of the spiral 

 travelling in two directions, those on this side of the 

 centre travelling from right to left, and those on the other 

 side in the reverse direction. Is this not a possible explan- 

 ation of Prof. J. C. Kapteyn's double-drift theory of 

 star motions? It explains why the two systems travelling 

 in opposite directions should be of equal composition and 

 proportions, but it necessitates that in the region of the 

 sky opposite to that in which the double drift has been 

 observed the drift should be simple. 



The explanation also presupposes that our stellar 

 system was once more closely aggregated, and because 

 there is no central core to our system it must be of less 

 bullc than that of the nebula of .\ndromeda. The two 

 stellar systems, once consisting of closely packed stars 

 and more or less spherical, travelling in opposite directions 

 and approaching each other within reach of the action of 

 gravitation, would have experienced disruption, each throw- 

 ing out equal equatorial prominences on the same prin- 

 ciple as that which produces the tidal bulges. On the 

 nearer approach of the two systems to each other, the 

 smaller of the two. our stellar system, would have experi- 

 enced the entire disruption which has reduced it to the 

 tenuity which it exhibits, whereas the larger stellar system, 

 the nebula in Andromeda, would have been enabled to 

 keep its central core. Ernest H. L. Schwarz. 



Rhodes University College, Grahamstown. Cape 

 of Good Hope. September 12. 



