220 



♦ KNOWLEDGE ♦ 



[Oct. 5, 1883. 



a number of citizens, all nuwilliiig to take the office, but ready to 

 do so as a duty when actually called to the work, no one would think 

 of calling the executioner a murderous ruffian. I apply that term 

 to each one of those who have been in the past, are now, or will 

 hereafter be (so long as our present sj'stem continues) eager can- 

 didates for an office which none but a murderous ruffian would 

 accept, if he could avoid it without failing in duty to his country- 

 men. If you can believe that the numerous applicants who have 

 come forward for the office within the past few weeks have done 

 so with a feeling of repugnance against taking life, but a feeling also 

 that it was theii' clear duty to offer themselves for the work, a painful 

 duty which they could not conscientiously avoid, — why then, you 

 can believe anything, and reasoning would be thrown away on j-ou. 

 Every one knows that the actual case is very different, that every 

 one of the applicants (every man Jack or Jack Ketch of them) has 

 deliberately sought to adopt man-killing as the business or part of 

 the business of his life. It is well, in the horror which the presence 

 of so many brutally-minded wretches amongst us must excite in 

 every rightly-constituted mind, to find that some of the " hangman 

 knaves" are ashamed to let their names be known, until sure of the 

 oj^ce. To compare soldiers with hangmen is sheer nonsense. A 

 soldier is primarily a man who takes as his office a part in the 

 work of defending his country at the risk of his own life and limbs. 

 His country may engage in wicked wars, and the necessities 

 of the service, the rules of its discipline, and so forth, 

 may make him one of the number of those employed in 

 wars of that particular kind. During the course of such wars his 

 hand may take away the lives of other men. But no soldier ever 

 gets enUsted with the thought that it would be a pleasant thing to 

 him to take away life ; whereas there never yet was an applicant 

 for the office of common hangman who was without this hideous 

 incentive. It would not be a bad thing for the future of this 

 country if every man who had publicly announced his readiness to 

 take away life, his eager hankering for the hangman's office, were 

 removed, along with his children and his nearest kinsfolk, to a 

 place where they could be kept apart from their fellow men till the 

 lot had in due course of nature died out. I say it would not be a 

 bad thing for the country, not that it would be just, especially to 

 the kinsfolk ; for in many cases these murderous folk are sports of 

 nature, their kinsfolk being often gently-minded, worthy people. 

 But it is terrible to think of these slaughter-loving men 

 marrying and multiplying their kind in our midst. — J. Terry 

 Patch. I think no such statement of the plan and pur- 

 pose of Knowledge at all necessary, after what has been so 

 clearly said (and so often) already. It seems to me unreasonable 

 to insinuate that Mr. Clodd intended " a sneer at the faith of 

 Christians" in speaking of the injunction to the Hebrews against 

 eating pork as not actually a revelation of God's will. (You misun- 

 derstand Mr. Clodd's use of "pseudo" in combination with the word 

 revelation ; he does not mean either a false revelation or the state- 

 ment of something false as if it were a revelation, but simply that 

 a certain statement has mistakenly been regarded as a revelation.) 

 Yoa might as reasonably accuse your neighbour at breakfast or 

 dinner of intending a covert insinuation against the faith of Christen- 

 dom when he takes ham with his eggs or bacon with his chicken ! 

 Eead what the reverend head-master of Clifton has said about 

 inspiration, and you will find abundant evidence that the ablest and 

 most learned theologians reject the idea of inspiration of the kind 

 you imagine, while the fiercest enemies of the faith you fancy you 

 are defending find in the doctrine of such inspiration the readiest 

 and most effective weapon of attack. No wonder with such 

 views as yours you think Knowledge not always neutral. How 

 could it be with such neutrality-laws as you woifld enjoin ? — 

 W.J. Bkindle. Your man-servant mistook a dark part of the moon 

 for an eclipse shadow. The mistake has been made before when 

 the moon has been five or six days past the full. " Whitakers 

 Almanac " naturally did not predict the occurrence, nor as you say 

 did " F.B.A.S." in " The Face of the Sky." The sympathetic inks 

 you describe hardly fulfil Mr. Wood's requirements.— Ja.s. Walker. 

 We do not undertake to work sums. But here is a general way of 

 working out such problems. Let h be the height of a right cone, 

 V its volume, and v the volume you want to cut olf by a plane 

 parallel to the base. (In your case c is V/3 for one section and 

 2V/3 for the other.) Let .r be the distance of the required section 

 from the vertex. Then we have the proportion 



y -.V.-.h': ,r' 

 whence you find ,r at once, because Y, r, and h are known.— D. 

 Maver. Your mathematical papers received, and kept for future 

 use. But other matter received earlier awaits insertion. Much 

 obliged to you for it.— E. G. S. So-called spiritualism is associated 

 with so much rascality that I would not care for papers explaining 

 how the tricks are usually done. — H. Jones. (1.) The telescopes 

 are different ; but not having seen one of them can express no 

 opinion as to their relative merits. (2.) "The Stars in their 



Seasons " quite different from " Xew Star Atlas " : the former is 

 constructed especially for England and places in about same north 

 latitude ; the latter is an atlas of tho whole star sphere, and as well 

 suited for any latitude, north or south, as for the latitude of London. 

 ■ — A New Header. Thanks for magic square, which I will insert 

 with description. I hope it is not one of those which have already 

 appeared in Knowledge ; but really have not time to hunt them all 

 up. This must be the last for the present of magic squaredom. — 

 W. H. MiLNEs. I am no authority in matters classical ; but it 

 seems to me there is a rather abrupt change of mood in the motto 

 Aut nunquam tentes aut perfice, and that two subjunctives or two 

 imperatives would be better. But I may be quite wrong. — C. H. 

 Marriott. Do not know who is the publisher of Mr. Chimmo's 

 book. A bookseller would be able to tell you. — A. G. Grenfell. 

 Scarcely. Should say advertising might be of use. — Naggdeibb. 

 Thanks for cutting with Capt. Delauney's nonsense. Hope the 

 spelling of name correct, and that he is not really a namesake 

 of the eminent Delaunay. — A. Hlbble. Thanks, but seldom have 

 room for translations, and when I do I translate them myself. — 

 Perplexed. Probably the difference arises from the way of 

 blowing. The correctness of the law for closed pipes, even with the 

 comparatively rough test you indicate shows that the law is sound 

 enough. — W. N. Huddy. Probably long continued pressure on the 

 eye during sleep had produced a temporary change of shape in the 

 lenses. — A Wellwisher. Very glad the notice led you to a useful 

 little book. — Welshman. Unfortunately do not know how bones 

 may be melted so as to be moulded into any required shape. 

 Should have thought it impossible. — ZER-rBBA-BEL. Know abso- 

 lutely nothing about masonic keys, and am therefore unable to 

 explain how the Tau figure is used in measuring the celestial globe. 

 — J. D. Am away from Nautical Almanack, but for your purpose 

 you should use that excellent work. It gives the K. A. of Polaris, 

 and for each day in October (or any other month) you can 

 readily find the time when Polaris is on the meridian either 

 above or below the pole. If we were to solve every such 

 problem which occurs to our numerous readers, we should find 

 time running rather short. — A Subscriber. The question is 

 momentous, and quite in my line as a student of mathematics, 

 astronomy, and so forth : — " Cu7i horses breathe with their nosebags 

 on them, filled with chaff and corn ?" Your humble opinion is, 

 " that they are then in a state of suffocation " ; and " for the last 

 seven years" you have "brought out a ventilating nosebag." 

 (Brought it out where and how ?) My humble opinion is that 

 horses, whether full of chaff and corn or not, can breathe and do 

 breathe, with their nosebags on them. I have a curious theory 

 that if they could not breathe they would cease to exist. But 

 perhaps if I had brought out a ventilating nosebag for seven years 

 I should think differently. Are not you rather full of chaff, by 

 the way ? — W. S. — I quite agree with you that it is a circumstance 

 full of terrible meaning that so many should have applied for that 

 horrible office. 



#ur iHattjcmatiral Column. 



MATHEMATICS IN OUR SCHOOLS.* 

 By Professor Henrici. 



PURE geometry seems to me to be of the greatest educational 

 value, and almost indispensable in many applications ; but it 

 has scarcely ever been introduced at Cambridge, the centre of 

 mathematics and mathematical education in England. 



Geometry and geometrical drawing, which teach how to represent 

 figures on a plane or other surface have been treated as arts un- 

 known at English Universities, and relegated to the drawing office. 

 Instead of this, they ought to be an essential and integral part of 

 the teaching of geometry in connection with the purely geometrical 

 methods. As far as the jirogress of science is concerned, this 

 neglect of pure geometry in England has been of little consequence 

 — perhaps it has rather been a gain. For science itself it is often 

 an advantage that a centre of learning becomes one-sided, neglects 

 many parts in order to concentrate all its energy on some particu- 

 lar points, and make rapid progress in the directions in which these 

 lie. 



But what may suffer, if one side of a science is not cultivated in 

 is the industry which would have gained by its applications. In 

 considering the teaching of any mathematical or other scientific 

 subject, we cannot at the present time neglect the wants of the 

 ever-increasing class of men who require what has been called 



* From Prof. Henrici's opening address to the section of Mathe- 

 matical and Physical Science, British Association. 



