March 14, 1889] 



NATURE 



4<^5 



required, and no axioms or postulates except Euclid's 

 may be assumed. The actual proofs of propositions as 

 given in Euclid will not be required, but no proof of any 

 proposition occurring in Euclid will be admitted in 

 which use is made of any proposition which in Euclid's 

 order occurs subsequently." 



The subject came on for discussion in the School on 

 January 26, 1888, and a grace finally passed the Senate 

 (March 8, 1888), making the alteration in the regulations 

 for the previous examination recommended in the Report. 



The Council of the Association then forwarded an 

 Address to Her Majesty's Civil Service Commissioners, 

 drawing their attention to the recent Reports of the 

 University Boards, and asking for corresponding altera- 

 tions in the regulations for the Woolwich and Sandhurst 

 examinations, as follows : 



" In view of the above facts, the Council feel themselves 

 justified in inviting the attention of Her Majesty's Civil 

 Service Commissioners to the desirability of a change in 

 one of the existing regulations for the examinations 

 conducted under their authority, especially those for 

 admission to Sandhurst and Woolwich. By this a 

 candidate is required to ' satisfy the Commissioners in 

 Euclid, Books I.-IV. and VI.' The Council, having 

 reason to believe that this regulation is very generally 

 understood to imply that Euclid's text is required without 

 any but mere verbal variations, beg to suggest that the 

 subject should be defined as ' Elementary Geometry to 

 the extent of Books I.-IV. and VI. of Euclid's "Ele- 

 ments," ' with a note to the effect that ' any proofs will be 

 admitted which are themselves sound, do not assume other 

 axioms than those of Euclid, and are not inconsistent 

 with the logical sequence of Euclid's theorems.' 



" The Council would prefer to have no particular text- 

 book prescribed, and to have the candidate's general 

 knowledge of geometry tested, rather than his power of 

 reproducing Euclid's text. 



" While making this request, however, the Council 

 wishes to express its acknowledgment of the high 

 character of the papers in Euclid set by the Civil Service 

 Examiners, and particularly of the frequent introduction 

 of stimulative exercises on the book work set. 



" The Council would esteem it a favour if they were 

 allowed to express their views on this important question 

 more at large by a deputation from their body at an 

 interview with the Commissioners." 



The following reply was received from the Com- 

 missioners : — 



" Civil Service Commission, June 30, 1888. 



"Sir, — I am'directed by the Civil Service Commissioners 

 to acknowledge the receipt of a circular signed by you in 

 behalf of the Council of the Association for the Improve- 

 ment of Geometrical Teaching, requesting that certain 

 changes may be introduced into the regulations for the 

 examinations held under their authority, and in particular 

 those for admission to Sandhurst and Woolwich ; 



"And, in reply, I am to acquaint you, for the informa- 

 tion of the Council, that the regulations for the military 

 examinations are framed and issued by the military 

 authorities, and that the Commissioners have no power 

 to alter them, but that the interpretation which the Com- 

 missioners have given them has been substantially in 

 accordance with the views expressed by the Cambridge 

 Special Board for Mathematics and the Oxford Board of 

 the Faculty of Natural Science. They have, that is to 

 say, instructed their occasional examiners to make no de- 

 duction from the marks allotted to a question because 

 a candidate substitutes another proof for Euclid's, if this 

 proof is a sound one and keeps to Euclid's sequence of 

 propositions. To remove any misconception which may 

 exist, the Commissioners propose to introduce a note to 

 this effect in the examination papers. It will be under- 

 stood, however, that they do not intend thereby to fetter 



their discretion of changing their practice whenever they 

 may consider it expedient. 



" In conclusion, while thanking the Council for their 

 offer to express their views on this question more at large 

 by the medium of a deputation from their body, the 

 Commissioners think that the agreement of their opinion 

 on this matter renders it unnecessary that the members 

 of the Council should give themselves the trouble of an 

 interview. 



" I have the honour to be. Sir, 



" Your obedient servant, 



" E. POSTE." 



Doubtless these concessions are in form the sorriest 

 minimum of change that could well be granted ; but the 

 spirit of the Reports is excellent, particularly if exam- 

 iners allow themselves, as it is quite open for them to do, 

 to interpret " Euclid's order" as his logical And not merely 

 his numerical order. Probably, if there is a strong desire 

 for further relaxation generally felt and expressed by 

 teachers, there will be no great difficulty in getting it 

 granted ; but it is by no means clear that such a desire 

 exists at present to a sufficient degree to bring pressure to 

 bear on the authorities. One does not easily see why the 

 sequence of the Syllabus and the " Elements " should 

 not have been granted as an alternative to that of Euclid, 

 as is done by the University of Edinburgh. These works 

 are the outcome of considerable discussion and delibera- 

 tion by practised teachers, and it seems scarcely right to 

 ignore them so entirely. As far as Cambridge is con- 

 cerned, there is one detail of reform which might be 

 effected without going beyond the terms of the grace of 

 the Senate ; i.e. the authorization of a list of additional 

 propositions not contained in Euclid's text, to be freely 

 used in the demonstration of all propositions subsequent 

 to the position they may be regarded as occupying in 

 Euclid's sequence. Such a list need not be long, and its 

 adoption would be a boon to those teachers who wish to 

 use the Syllabus. 



ELECTROSTATIC MEASUREMENT} 



THE number of electrostatic units of potential or elec- 

 tromotive force in the electro-magnetic unit of 

 potential is essentially a velocity, and experiments have 

 proved it to be so nearly equal to the velocity of light 

 that from all the direct observations hitherto made we 

 cannot tell whether it is a little greater than, or a little 

 less than, or absolutely equal to, the velocity of light. 



Sir W. Thomson is engaged now in making a set of 

 electrometers which will measure by electrostatic force 

 potentials of from 40 volts to 50,000 volts. The stan- 

 dardization of these instruments up to 200 or 300 volts 

 is made exceedingly easy, by aid of his centiampere 

 balance and continuous rheostat, with a voltaic bat- 

 tery of any kind, primary or secondary, capable of 

 giving a fairly steady current of ^ of an ampere 

 through it and the platinoid resistance in series with it. 

 The accuracy of the electro-magnetic standardization, 

 within the range of the direct application of this method, 

 is quite within ^V per cent. A method of multiplication 

 by aid of condensers, which was explained, gives an 

 accuracy quite within ^5 per cent, for the measuremerjt 

 in volts up to 2000 or 3000 volts ; and with not much less 

 accuracy, by aid of an intermediate electrometer, up to 

 10,000 volts. Such a potential as 10,000 volts is con- 

 venient for measurement by an absolute electrostatic 

 balance, which was fully explained in the lecture, and 

 illustrated by a drawing. But hitherto he has not been 

 able to make sure of the absolute accuracy of the electro- 

 static balance to closer than ','2 per cent. The results of 

 a great number of measurements made in the Physical 

 Laboratory of the University of Glasgow during the last 



" Abstract of part of Sir William Thomson's Royal Institution Lecture of 

 Friday evening, February 8, relating to the veloaty of h«ht. 



