5^4 



NATURE 



[February 23, 191 1 



Society is considering certain questions connected with 

 the educational curriculum of pharmaceutical chemists and 

 of chemists and druggists with the view of framing bye- 

 lays in pursuance of the powers vested in them by the 

 Poisons ■ and Pharmacy Act, 1908. At the present time, 

 candidates for the qualifying examination in pharmacy are 

 not required to undergo a systematic course of instruction, 

 and it is no part of the duty of the society to inquire how 

 or where they were educated. In the absence of a com- 

 pulsory curriculum, " cramming " is very prevalent in 

 connection with this examination, the result being a high 

 percentage of failures. Thus last year, out of 1027 candi- 

 dates who entered for the examination, 620 were un- 

 successful. Before actually proceeding to frame bye-laws, 

 the council of the society has drafted a scheme, which has 

 been submitted to pharmaceutical associations in all parts 

 of the country and to the principals of schools of phar- 

 macy, with the object of eliciting expressions of opinion 

 on the matter. The draft scheme suggests that the 

 examination be divided into two parts, and that a candi- 

 date desiring to enter for the intermediate examination 

 shall produce evidence that, subsequent to passing the pre- 

 liminary examination and being registered as a student, he 

 has attended, in a teaching institution approved by the 

 council, not fewer than 50 lectures in botany, 100 lectures 

 in chemistry, and 25 lectures in physics, and has done 

 25 hours' work in practical botany and 300 hours' work 

 in practical chemistry. As to the final examination, it is 

 proposed to require candidates — ^who must have been 

 engaged for three years in the ordinary work of pharmacy 

 under the supervision of a pharmacist — to produce evidence 

 of having attended at a recognised institution 60 lectures 

 and demonstrations in materia medica, 30 lectures in phar- 

 macy, and 20 lectures in dispensing and prescription Latin, 

 and of having done 200 hours' work in practical pharmacy 

 and 100 hours' work in practical dispensing. The pro- 

 posals have already been discussed by a number of 

 pharmacists' associations, and divergent opinions have been 

 expressed. While some are in favour of adopting the 

 scheme, others are pressing more especially for a modifira- 

 lion of that part of the proposed curriculum which pre- 

 cedes the intermediate examination, and the council is 

 being urged to consider the advisability of accepting the 

 certificates of other examining bodies in lieu of the inter- 

 mediate examination. 



SOCIETIES AND ACADEMIES. 



London. 

 Royal Society, February 16.— Sir Archibald Geikie, K.C.B., 

 president, in the chair. — W. Rosenhain and S. L. 

 Archbutt : The constitution of the alloys of aluminium 

 and zinc. In connection with researches on light alloys, 

 carried out on behalf of the Alloys Research Committee'of 

 the Institution of Mechanical Engineers, the authors have 

 studied the constitution of the Al-Zn alloys by pyrometric 

 and microscopic methods, including the study of specimens 

 after prolonged annealing at definite temperatures and after 

 quenching. The results are represented in an equilibrium 

 diagram differing materially from those previously put for- 

 ward. The principal points of difference are : — ^(i) The 

 liquidus curve shows a small break at a concentration of 

 85 per cent, of zinc, this break being connected with the 

 formation of a definite compound of probable formula 

 Al,Zn,. (2) In alloys under conditions of complete 

 equilibrium the occurrence of eutectic ceases at a concen- 

 tration of about 78 per cent, of zinc, although in ordinary 

 slowly cooled alloys the eutectic can be traced down to the 

 vicinity of 50 per cent. zinc. (3) At a concentration of 

 about 78 per cent, of zinc, the solidus curve of the allovs 

 rises abruptly from the eutectic line (380° C.) to a hori- 

 zontal line of arrest points at 443° C. This line com- 

 inences at the break in the liquidus curve already men- 

 tioned, and extends to about 37 per cent, of zinc ; between 

 78 and 40 per cent, this line represents the solidus, but 

 near_ 40 per cent, the solidus bends upwards towards the 

 melting point of pure aluminium. The reaction indicated 

 by this line of arrest points is the formation of a com- 

 pound (Al^Zn,) by the reaction of crystals of a solid solu- 

 tion of zinc in aluminium with the residual liquid. (4) A 

 second horizontal line of arrest points of considerable 

 NO. 2156, VOL. 85] 



intensity has been found at 256° C. in alloys containing 

 99 to 35 per cent, of zinc. These heat evolutions are due 

 to decomposition of the compound (Al^Zn,) into two phases, 

 one of which is the saturated solid solution of Zn in Ai, 

 while the other is practically pure Zn. (5) The existence 

 of a definite compound is indicated, stable only between 

 443° C. and 256° C, and having a zinc content of about 

 78 per cent., most nearly represented by Al^Zn,. Evidence 

 for its existence is derived from the termination of the 

 eutectic line and the position of maximum intensity of the 

 line of heat evolutions just mentioned ; this is strikingly 

 confirmed by the micro-structures, which show the com- 

 pound in the form of characteristic hexagonal dendrites. 

 When decomposed (at or below 256° C), it exhibits a 

 duplex laminated " pearlitic " structure strikingly re- 

 sembling the pearlite of carbon steel. — R. WhiddinKton : 

 The production and properties of soft Rontgen radiation. 

 Rontgen rays from ordinary bulbs are usually produced at 

 generating potentials of between 10,000 and 100,000 volts. 

 It is possible by using a special tube with a very thin 

 aluminium window to experiment with rays generated at 

 only a few hundred volts. The rays dealt with in this 

 paper were generated at 1000 to 3600 volts. It has been 

 found that such soft Rontgen rays have much the same 

 properties as the harder rays usually experimented with. 

 They produce ionisation in air, affect photographic plates, 

 and can excite secondary radiations when incident on solid 

 bodies. Their range in air, however, is not many centi- 

 metres. For many purposes a Rontgen radiation is 

 sufficiently defined by a knowledge of (i) the total energy ; 

 (2) the penetrating powers in absorbing screens. These 

 two properties have therefore been investigated in some 

 detail, with reference particularly to the influence exerted 

 by (i) the material of the antikathode ; (2) the potential at 

 which the rays are generated. The antikathodes used fall 

 naturally into two groupings : — Group A. — Al, Pt. Group 

 B.^Ag, Cd, Cu, Fe, Ni, Pb, Sb, Sn, Zn. The anti- 

 kathodes of Group A emit secondary radiations, those of 

 Group B do not. Experiment indicates that Al emits a 

 soft characteristic radiation of \/p 580 (in Al). In order to 

 arrive at a common explanation of a number of experi- 

 mental results, it is suggested that this Al radiation dis- 

 obeys the law of " Rontgen ray fluorescence " recently 

 advanced by Barkla. — ^Prof. J. Eustice : Experiments on 

 stream-line motion in curved pipes. In a paper on the 

 flow of water in curved pipes, the author has shown that 

 during the flow of water through a pipe, if a change is 

 made from a straight to a very slightly curved form, there 

 is an increased resistance to flow, which is very marked 

 at velocities below the critical velocity. In order to find 

 the cause of the increase in resistance, an apparatus was 

 designed which provides for the distribution of six variously 

 coloured filaments of dyed water into a glasSjpipe through 

 which water is flowing. The positions of the filaments can 

 be so arranged that in the passage of water from a straight 

 to a curved pipe the directions of the stream-lines in any 

 part of the tube can be investigated. The experiments 

 show that the curvature of a filament is less than the 

 curvature of that part of the pipe in which the filament 

 is flowing, and if the velocity of flow increases the curva- 

 ture of the filament increases. The filaments impinge on 

 the outer wall of the pipe, and, flattening into bands, 

 follow the surface of the pipe and cross over to the inner 

 wall, where the filaments start again" in their path along 

 the main stream, until (if the pipe is sufficiently long) the 

 filaments again meet the outer wall, when the return flow 

 along the surface is repeated. A filament flowing in the 

 central plane of the pipe, when reaching the outer wall, 

 divides into two parts, which come together on the inner 

 wall of the pipe ; the other filaments flow through the loop 

 which is thus formed. A filament not in the central plane 

 remains on that side of the plane in which it enters the 

 curved pipe. The experiments were extended to angle 

 pip)es, and the velocities were increased until turbulent 

 motion was obtained. After flowing through a curved pipe 

 or angle, vortices are generated which persist in a con- 

 tiguous straight pipe. 



Challenger Society, January 25.— Dr. C. H. Fowler in 

 the chair. — Commander Campbell Hepworth : Remarkable 

 displays of phosphorescence in the sea. These displays 

 took the form of rapidly moving curved bands of lumin- 



