March 13, 1890] 



NATURE 



441 



and ith'f respectively. Then, from any point S on the 

 circumference of the circle, reproject the six points dht, d'h'i', 

 upon the same circumference in the points similarly lettered. 



By means of this double projection from the centres E and i the 

 points DHT have been transferred in duplicate from the hyperbola 

 to the circle, or from one conic to another of a different species ; 

 and it is proved in treatises on modern geometry that points so 

 transferred lose none of their projective properties. Hence the 

 points dhi and d'/i't" on the circumference of the circle are allied 

 projective systems. Therefore, in order to find the perspective 

 line common to both systems, choose one point t of the first set 

 as the centre of projection of the second system ; and make f, 

 the correlative point of the second set, the centre of projection 

 of the system dht. 



From t project the points d' and h' by rays td' and tk', and 

 from f project the correlative points d and h by rays i'd and t'/i. 

 Then the correlative rays td' and t'd will intersect in a point d^ 

 on the required perspective line ; and the correlative rays th' 

 and t'h will meet in h^, a second point on the same line. This 

 perspective line d(^h^^ will intersect the circumference in two 

 points ?■(, and ^^ which, being joined to S and produced, will 

 determine the double points I and g common to the hyperbola 

 and transversal Lz. The complete quadrangle ECTC shows 

 that the harmonic ratios Czi'N and gzlL. are segments of the 

 same harmonic pencil P. 



The lines Es and C'z are tangents to the curve at E and C 

 respectively ; and z is the pole of the polar EC with respect to 

 the hyperbola. The proofs of these last two deductions may be 

 found in any good text-book on geometry of position. 



Robert H. Graham. 



Thought and Breathing. 



Prof. Max MUller's article on thought and breathing, in 

 your issue of February 6 (p. 317) has just come into my 

 hands. In it he states that the power of retaining the breath 

 is practised largely by Hindus as a means towards a higher object, 

 viz. the abstraction of the organs of the human body from their 

 natural functions. The same custom prevails amongst a certain 

 sect of Mahometans also — the so-called Softas. 



In 1878, when in the Central Provinces of India, I came 

 across a native Christian — Softa Ali, as he was called — who had 

 a history. His father had been a Cazi — or religious judge — and a 

 wealthy man, who through scruples of conscience fell into dis- 

 grace with a certain native ruler, lost his all, and was banished. 

 His son was, or became, a Softa, and after some years embraced 

 Christianity from conviction, and at great cost to himself — for 

 his wife and children would no longer consort with him. When 

 describing to me the practices formerly enjoined upon him by 

 his religion, this man stated that a Softa is required to draw in 

 and retain his breath and respire it again in various manners. 

 He did not give full details as to how this should be effected, 

 but said that the object of this procedure was to worship with 

 every organ of one's body — heart, lungs, &c., in turn. He 

 added that this practice was a fruitful source of heart-disease. 



The following year, when staying at Futtehpore Sikri, near 

 Agra, I saw and heard a Mahometan, unknown to himself, make 

 his evening devotions near the tomb of Suleem Chisti in the 

 way above described ; his movements, and the sounds he uttered, 

 were most peculiar. 



It has been often related, from well-attested evidence, that in 

 the case of those who have been recovered from drowning, or of 

 those who have been hung and cut down before life was extinct, 

 a kind of automatic consciousness seems to be extraordinarily 

 active in them at the time of their peril. It would appear that, 

 as regards Hindu and Mahometan devotees, and the drowning 

 or partially hung man, a kind of asphyxia is the result, and 

 that, when sensation is almost gone, the intelligence acquires 

 increased activity. In our ordinary life, if our minds are in- 

 tently fixed upon a subject, we instinctively and involuntarily 

 retain the breath. 



When in Rajputana, and again when on the frontier of 

 Chinese Tibet, I saw in each place a man who, to all appear- 

 ance, seemed to have attained the power of perfect abstraction. 

 In the former case, the villagers asserted that the devotee rose 

 only once a week from his most uncomfortable and constrained 

 position ; in the second instance, the man — a most singular-look- 

 ing person — remained absolutely immovable the whole day. 

 Both seemed to be in a kind of cataleptic trance. 



Harriet G. M. Murray-Aynsley. 



Former Glacial Periods. 



I HAVE long felt convinced that geologists are being misled in 

 reference to former glacial epochs by failing to give due thought 

 to a consideration referred to on former occasions,* viz. that 

 when the present surface of the globe has been disintegrated, 

 washed into the sea, and transformed into rock, there will un- 

 doubtedly then be about as little evidence that there had been 

 a glacial epoch during post-Tertiary times as there is at present 

 that there was one during Miocene, Eocene, Permian, and other 

 periods. James Croll. 



Perth, March 6. 



A USTRALASIAN ASSOCIA TION FOR THE 

 ADVANCEMENT OF SCIENCE. 



THE formation of this Association, mainly by the 

 efforts of Prof. Liversidge, of Sydney University, and 

 its first meeting in Sydney in August 1888, were noticed 

 at the time in Nature (vol. xxxviii. pp. 437, 623). One 

 of the chief rules of the Association is that it shall meet 

 in turn in the capital cities of the various colonies ; and 

 Melbourne was agreed upon as the second meeting-place. 

 It was found inconvenient, however, to hold the Mel- 

 bourne meeting during 1889, as should have happened in 

 due course, for it is only after Christmas that all the 

 Universities are simultaneously in vacation ; and accord- 

 ingly it was commenced on the 7th of January in the 

 present year, and was continued through the following 

 week. Some anxiety was felt as to the result of this choice 

 of date, for there is always a risk in January of such con- 

 tinuous heat as would hinder the work and destroy the 

 pleasure of the meeting ; but the Association proved to 

 be specially favoured in the matter of weather. 



The following are the names of the officers of the 

 Association and of the Sections. With regard to the 

 latter, the rule obtains that Presidents are chosen from 

 other colonies, while Vice-Presidents and Secretaries are 

 chosen from the colony in which the meeting is held. 



President, Baron von Mueller, K.C.M.G., F.R.S. 



Local Treasurer, R. L. J. Ellery, C.M.G., F.R.S. 



General Secretaries : Prof. Archd. Liversidge, F.R.S., 

 Permanent Hon. Secretary ; Prof. W. Baldwin Spencer, 

 Hon. Sec. for Victoria. 



Assistant Secretary for Victoria, J. Steele Robertson. 



Sectional Officers : — Section A (Astronomy, Mathe- 

 matics, Physics, and Mechanics) — President, Prof. Threl- 

 fall, Sydney University. Vice-President, Prof. Lyle, 

 Melbourne University. Secretaries : W. Sutherland, E. 

 F. J. Love. 



Section B (Chemistry and Mineralogy) — President, 

 Prof. Rennie, Adelaide University. Vice-President, C. 

 R. Blackett, Government Analyst, Melbourne. Secretary, 

 Prof. Orme Masson, Melbourne tlniversity. 



Section C (Geology and Palaeontology — President, 

 Prof. Hutton, Canterbury College, New Zealand. Vice- 

 President, Prof. McCoy, C.M.G., F.R.S., Melbourne 

 University. Secretary, James Sterling, 



Section D (Biology) — President, Prof. A. P. Thomas, 

 Auckland. Vice-Presidents : J. Bracebridge Wilson ; 

 P. H. MacGillivray. Secretaries : C. A. Topp, Arthur 

 Dendy. 



Section E (Geography) — President, W. H. Miskin, 

 President of the Queensland Branch of the Royal Geo- 

 graphical Society of Australasia. Vice-Presidents : Com- 

 mander Crawford Pasco, R.N.; A. C. Macdonald. 

 Secretary, G. S. Griffiths. 



Section F (Economic and Social Science and Statistics 

 — President, R. M. Johnson, Registrar-General, Hobart. 

 Vice-President, Prof. Elkington, Melbourne University. 

 Secretaries : A. Sutherland, H. K. Rusden. 



Section G (Anthropology)— President, Hon. J. Forrest, 

 C.M.G., Commissioner for Crown Lands, Western 



' Quart. Joum. Geol. Soc. for May 1889 ; " Climate and Time," p. 266. 



