QCTI IBEK 31, [918 



NATURE 



179 



industries; and (c) in Birmingham in respect <>f the 

 1. rmentation industi . the lack of any 



. .illv adequate provision in this country for the needs 

 ol equal!} importanl branches ol industry which depend 

 upon ili' 1 ling oi 1 ei tain well-defined 



groups of natural (and chief!} vegetable) raw materials. 

 I'h.- technology oi the following groups of natural 

 li 1 ted because of their ini 

 importance, and ol their close relationships 

 with thi' work already developed in the botany depart- 

 ment [I can scarcer; bi doubted that the studj and 

 ition of their chemical properties, treatment, 

 and uses i'i tii. Department of Chemical Technology 

 will constitute an important link, not only with the 

 . partment, but also with th< 

 economii development of the vegetable resources ol 

 the Empire, on which -rounds their adoption by the 

 college may b< 1.II3 appropriate, The 



products in qui IS follows : — (i) Celluloses, 



starches, gums, dextrins, and resins; 

 mal and vegetable oils and fats, and the 

 manufacture of glyci and food products 



(e.g. margarim >m; and (iii) rubber and 



similar materials. 



Industrial Connection. 

 In the development of thi foregoing scheme as a 

 whole, emphasis is to l» laid upon the importance of 

 everything possible being done, both now and in the 

 il shing and extending con- 

 between tin various sections of the Depart- 

 ment and the industries which thej are severalty 

 designed to serve. The Department will also keep in 

 1 lost touch with the various organised efforts that 

 are now being made to solv< general industrial and 

 economic problems b\ co-operativi investigation and 

 1 ch. 

 The additional financial requirements for the im- 

 portant developments outlined abovi are estimated at 

 for buildings and equipment, and not less 

 than 10 .000/. a year for maintenance and working 

 expenses. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 

 London. I he following doctorate has been con- 

 ferred bj the Senate: — D.Sc. [Engineering): Mr. 

 Miles walker, an external student, for a thesis 

 'Supply of Single-phase Power from Three- 

 ms." 



Teai hers have hitherto exercised but little influence 

 on :ln public educational systems of this country. 

 But if the public authorities thai control this educa- 

 to exercise their growing power to the best 

 advantage, the) can scarcely do so without the in- 

 creasing help of the teaching profession. The 

 Teachei -' Ri g ttion < presentative of 



ssion " was 1 stablished in 1912. 



During its short life it has rendered valuable service 

 to English education b\ pn-parinj; a registoi nl 



teachers and b) providing 1 parliament. But 



it the teaching profession is 1.1 take an effective pari 

 national system of education, it 

 1 an best do so by co-operating with the existing 

 authorities on the lines indicated by the Whitley 

 report. The initiative will probably have to come 

 from tin teachers. The Teachers' Registration 

 Council can provide their side of the "Joint Indus- 

 trial Council." but provincial councils of teachei s an 

 needed to provide their side of the "district councils." 

 Accordingly a new step has been taken by the forma- 

 tion, at a meeting held in Manchester on October 26, 



NO. 2557. vol. 102] 



of the first provincial council, representative oi the 

 teaching profession in Lancashire and Cheshire. The 

 council consists of two representatives of each of thi 

 t niversities Manchestei and Liverpool- and of the 

 teachers' associations in ies. It is antici- 



pated that other provincial councils will quicklv be 

 set up elsewhere. Their establishment throughout 

 the length and breadth of England will not only 

 enable the teachers i" exercise .1 profoundly beneficial 

 influence upon the organisation of local education, 

 but also be the means of securing .1 gi 1 mi 

 ol life and liberty for the teaching profession. 



SOCIETIES AND ACADEMIES. 

 London. 



Optical Society. October to. Prof. Cheshire, presi- 

 dent, in the chair. -T. Y. Baker: Sources .and ma 

 tude of centring errors in a sextant. A centring erroi 

 in .1 sextant is ordinarily- due to the sextant bi 

 placed eccentrically on the dividing engine. In ordei 

 to complv with the National Physical Laboratory's 

 "A" class certificate, it is necessary that this eccen- 

 tricity should not be such as to produce errors in th< 

 reading exceeding 40 seconds. This condition is 

 satisfied provided the scale-centre lies within a certain 

 ellipse the centre of which is the mechanical centre 

 of the instrument,, and the axes of which lie one along 

 and the other at right angles to the line of the middle 

 reading. The semi-axes of this ellipse for a 7-in. sex- 

 tant reading up to 120 are 5-2 mils and 0-7 mil 

 respectively,' but the former figure needs reduction to 

 about 3 mils in order to allow of the vernier not 

 reading " long " at the two ends of the scale. The 

 customary practice of sextant-makers has been to re- 

 adjust the position of the mechanical centre after the 

 instrument "has had the scale engraved. The work- 

 shop method of testing whether such readjustment is 

 necessary is customarily the method of trying the 

 length of the vernier against the scale at different 

 points along the arc. The author showed that this 

 method is not a sufficiently delicate test for the pur- 

 pose of complying with the' "A" certificate. An alter- 

 native method was described, in which the correct- 

 ness or otherwise of the centre is determined by the 

 tracing of a mark engraved upon the vernier against 

 a circular arc cut from the same centre and at the 

 same time as the marking of the scale. This method 

 is being adopted bv the Admiralty, and is already- 

 embodied in their specification for cadets' sextants. — 

 T. Chaundy : Astigmatism : interchangeability of stop 

 and obiect. For an object at O and a stop at S on the 

 axis of an optical instrument, the astigmatism (i.e. 

 astigmatic separation divided by the square ol the 

 height of the object! is to least order 

 /.(I-FO.FS//W.SO, 

 her with a quantity symmetrical in O and S. 

 The planes of stop and object may thus be inter- 

 changed without change in value of the astigmatism 

 if FO.FS = / 2 . In this case, with like end-media. 

 F', S\ O' (the images of F, S, O in the instrument) 

 are sy'mmi ri ' placed with respect to F, O, S. In 

 particular, an object at one focus and a stop at the 

 ,,,!„., ar e interchangeable. The astigmatism in 

 rase i~ unaltered by reversal of the instrument 

 consequen 1 mvenience in calculation is pointed 

 In particular, all the primary aberrations tree b 

 mined by differentiation of'its expression ii ol 



the pow ■ 1 s and separations of the system 



Royal Microscopical Society. Octobei r<5 I E. 

 Barnard: A new illuminant for, microscopical work. 

 Note on the reoorts of the M earch Com- 

 mittee on the standardisation ol patl gical methods. 



