298 



NATURE 



[September 2, 1909 



Engineering units of measurement form the subject of 

 a pamphlet which has just been produced by Mr. J. 

 Ramsay, of the Glasgow and West of Scotland Technical 

 College. The greater part of the thirty-six pages consists 

 of definitions of the quantities and symbols which more 

 commonly occur in engineering, and in each case the 

 author gives both British and metrical units, together with 

 the connection between them. Several useful tables are 

 given at the end. The value of the pamphlet will be 

 appreciated when it is remembered that students of 

 engineering in this country are compelled to use both 

 British and metrical systems of measurement, a condition 

 which tends to produce much mental confusion and hinders 

 progress. While most of the author's explanations a.e 

 good, we do not think that his remarks on pp. 8 and 9 

 regarding weight, mass, and gravitational and dynamical 

 units of force are sufficiently clear ; but few writers have 

 succeeded in producing absolutely convincing statements 

 when they take, as the present author does, the British 

 gravitation unit of force as the force with which the earth 

 attracts a pound weight at the sea-level at Greenwich, and 

 also a unit of mass of 32-2 Ih. The publishers of the 

 pamphlet are Messrs. John Smith and Son, Glasgow, and 

 the price is \s. net. 



OVR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in September : — 



Sept. I. i6h. om. Mars in conjunction with Moon (Mars 

 i°4'S.). 



2. I7h. om. Saturn in conjunction with Moon (Saturn 



I°I4'N.). 



3. 9h. 2m. to 9h. 50m. Moon occults {' Ceti (mag. 4'5). 

 7. Maximum of Mira Cell (mag. 3'3-8'5). 



10. Saturn. Major axis of outer ring =45'3l", Minor 

 axis = lO'oo". 



15. I2h. 5m. Minimum of Algol {$ Persei). 



16. 22h. om. Mercury at greatest elongation (26° 34' E.). 

 18. 8h. 54m. Minimum of Algol (/3 Persei). 



23. 22h. om. Mars at opposition to the Sun. 



,, I5h. 3m. Uranus in conjunction with Moon (Uranus 



2'35'N.). 

 ,. 3ti- 39«i- to 4h. 53ni. Moon occults a Sagiltarii 



(mag. 2-1). 

 28. I5h. om. Mars in conjunction with Moon (Mars 



o°9'N.). 

 30. oh. om. Saturn in conjunction with Moon (Saturn 



i°8'N.). 



The South Polar Spot on Mars. — With regard to the 

 recent observation by M. Jonckheere, Dr. Lohse records 

 in No. 4348 of the Astronomischc Nachrichten (p. 61) that 

 he observed the bright patch which has detached itself 

 from the polar snow-cap on .'\ugust 8. The position of 

 the spot, in areographical coordinates, was : — longitude, 

 304-5°; latitude, -74-5°. A measure of the south polar 

 spot gave a diameter of about 30°. 



Comet 19096 (Perrine, 1896 VII.). — The position of 

 comet 19096, according to the ephemeris given in No. 4348 

 of the Astronomische Nachrichten, on September 3 will 

 be o (19100) = ih. i2-9m., 5= +46° 24-8', whilst that on 

 September 15 will be a = 2h. om., 5=4-51° 32-9'. Thus 

 we see the comet is passing from Andromeda to Perseus, 

 and on September 9 will pass about half a degree north 

 of V Persei ; at the same time it is approaching both the 

 earth and the sun, and is now about one magnitude brighter 

 than when re-discovered. 



The Orbits of Certain Spectroscopic Binaries. — Nos. 

 '5 and 17, vol. i., of the Publications of the Allegheny 

 Observatory deal, respectively, with the orbits of the 

 spectroscopic binaries tt* Orionis and f Lyrs. The former 

 is discussed by Mr. R. H. Baker on the basis of thirty- 

 six spectrograms obtained with the single-prism Mellon 

 spectrograph. The orbit is nearly circular, the eccentricity, 

 NO. 2079, VOL. 81] 



in the final elements, being given as 0027 + 0013, and the 

 length of the semi-major axis is 3,393,000 km. ; the ampli- 

 tude of the velocity-variation is 518 km., and the period 

 is 95 days. The spectrum is of the helium type, but does 

 not show the spectra of both components. Mr. F. C. 

 Jordan finds, from the discussion of si.xty-four plates, that 

 the orbit of f' Lyrjc is circular and the period is 4-29991 

 days; the amplitude of the variation is 102-48 km. 



Mr. Jordan has also observed four of the stars in Taurus 

 which Prof. Boss suggested belonged to a group having a 

 common movement. He finds (Publication No. 16) that 

 two of the four stars, Piazzi 234 and Bradley 716, give 

 results in accordance with the idea that they belong to a 

 cluster; the other two, 51 Tauri and 1 Tauri, appear to 

 have variable velocities. 



The Bolide of April 20 as observed in Fran'CE. — The 

 August number of the Bulletin de la Society astronomique 

 de France contains a number of drawings and descriptions 

 (PP- 357~60 of t^^ remarkable meteor seen on April 20 

 at about 10 p.m. This meteor traversed Ursa Majorj 

 leaving behind it a train which lasted for about two 

 minutes as a naked-eye object, according to M. Ou^nisset, 

 and could be seen for five minutes with a prismatic 

 binocular. The train moved in an east-and-west direction, 

 and developed a condensation, which is shown by some 

 observers as being at one side of a break in the train, and 

 by others, M. Qu^nisset among them, as a bright loop. 

 The brightness of the meteor was about equal to that of 

 Venus at its brightest, whilst that of the train was com- 

 parable with the brightness of the Milky Way. 



MATERLi MEDICA AMONG THE ZULUS. 



I N the July number of the Annals of the Natal Govern- 

 ■'■ ment Museum, Father A. T. Bryant, a competent 

 observer of native life and author of a valuable dictionary 

 of the tribal language, has for the first time collected 

 materials for the study of Zulu materia medica and the 

 methods of the local medicine-man. He records some 

 240 Zulu plants used in medicine, giving what the people 

 believe to be their properties and the modes in which 

 they are administered to the patient. Here, as among 

 other savage races, the medicine-man was a personage 

 originally distinct from the diviner or so-called witch- 

 doctor ; but their functions tend occasionally to overlap, 

 the medicine-man dealing largely in magic and charms, 

 while the witch-doctor makes himself familiar with 

 curative herbs, though his real business is to indicate or 

 " smell out " the agency which is supposed to have caused 

 the illness. 



The Kafir medical man has no knowledge of pathology. 

 He knows as much of anatomy as can be learned from 

 cutting up cattle for food ; but the nervous system is a 

 complete mystery to him, and though he has observed 

 that the blood runs through the body, he does not 

 associate its circulation with the beating of the heart. 

 He works by the examination of symptoms, though he 

 is ignorant of their cause, treating paraplegia, for 

 instance, by local applications, and not connecting its 

 occurrence with any brain disease. His occasional 

 successes seem to be generally due to the influence of 

 suggestion, by exciting the feeling of confidence or 

 imagination which summons into action the remarkable 

 recuperative powers of the patient. In his profession 

 medicine and magic constitute a single art, and he is 

 called upon to combat, not only the disease which has 

 actually shown itself in the system, but also the machina- 

 tions and forms of the black art which arc believed to 

 have induced it. 



Like most savages, the Zulu is unusually susceptible 

 to new diseases, though he is hardened against those 

 which are old. Father Bryant gives interesting details 

 of the more common diseases and their popular treatment. 

 He records a form of disease, believed not to be known 

 to medical science, resulting from an intestinal parasite 

 developing into a species of beetle. The local form of 

 phthisis seems to be different from that of Europe, the 

 former setting in at the bottom, the latter at the top, of 

 the lung. The medicine-man deals largely in blood- 

 letting, poulticing, the use of ointments, the clyster and 



