472 



NA TURE 



{April 13, 1876 



knife-edge by means of which the recording lever is set 

 in motion is fixed, can be varied in length ; and this 

 makes it possible to vary the magnifying power of the 

 lever, because the distance of the knife- edge from its axle 

 can be changed. Such an addition has always been 

 a desideratum, even in the wrist sphygmograph. The 

 screw, c, clamps the two component parts in any desired 

 position. A second reserve knife-edge, D, can also be 

 turned up to replace the ordinary one, A, when the 

 cardiac action is extraordinarily forcible. By the screw, 

 K, the compress-spring is fixed. L is the secondary spring, 

 which prevents the recording lever from quitting the 

 knife-edge ; it can be thrown out of gear when not 

 required. 



The supporting bars are seen at H H ; they re- 

 placing the side-lappets of the original instrument. On 

 them are fixed uprights, G G G, on which again are 

 attached by screw-clamps two transverse bars for the 

 suspension of the sphygmograph. That to which the 

 clock-work end is joined can only be moved upon the 

 uprights with which it is connected. The other has an 

 additional sliding-piece, i, that allows of the screw-pad 

 portion being independently raised or lowered in a hinged 

 manner. 



That this suspending stage will prove of great service 

 in the study of the heart's action there can be no doubt. 

 The presence of the large number of movable centres 

 must, however, render its adjustment somewhat difficult. 

 It will be seen in the figure that the recording plate above 

 the watch-work is of considerable depth. We have found, 

 practically, that it is never advantageous to allow the 

 oscillations of the lever to reach nearly so great an am- 

 plitude as this will permit ; and it is known by all that it 

 is very important that the average level of the lever's 

 tracing should never be far above that line which is per- 

 pendicular to the tangent of the circle formed by the 

 lever in its movements, at the point where the two cut 

 one another. 



Whilst on the subject of Dr. Galabin's cardiograph 

 and sphygmograph work, we may incidentally draw at- 

 tention to a point in a paper by him in the January 

 number of the J OJirnal of Anatomy and Physiology. Dr. 

 Galabin there comments on Mr. Garrod's law respecting 

 the length of the cardiac systole as it appears in the 

 arterial system — that it is constant for any given pulse- 

 rate, and varies as the cube root of the rate. He remarks, 

 " I have found the length of the systolic portion of the 

 pulse-curve to deviate somewhat considerably from that 

 deduced from the equation. ... It appears to be approxi- 

 mately true in normal pulses." Would it not have been 

 better if Dr. Galabin had given a larger number of 

 examples — he having confined himself to two, of which 

 one is pathological ? In the paper in which the law 

 was announced, the agreement of the measurements with 

 the requirements was very close, and others have been 

 published since, even more satisfactory ; it has also been 

 indicated by its author that a pathological condition, like 

 anaemia (the instance taken), is just such an one as that 

 in which a deviation might be expected. Mr. Edgar 

 Thurston, of King's College, has recently read a paper 

 before the Medical Society of that School, which is 

 quite in confirmation of the law as originally stated, from 

 a considerable number of observations on healthy sub- 

 jects. 



PHYSICAL SCIENCE IN SCHOOLS 



T^R. WATTS quite puzzles me. I can see no contra- 

 ■■--' diction between the passages from my essay of 

 1867 and my letter of 1876, which he silently places in 

 juxtaposition. What I said in 1867 was (p. 261) that 

 *' science should be introduced into a school, beginning 

 at the top and going downwards gradually to a point 

 which will be indicated by experience." What I say in 



1876 is that experience shows, as far as I can judge, that 

 it is not generally wise to go down very far ; that one soon 

 comes to a point at which the loss in teaching science 

 counterbalances the gain. I am quite as sure as ever 1 

 was of the value of science in schools, in its right place. 



I think that those who advocate the teaching of science 

 to young boys scarcely reahse the difficulty of establish- 

 ing their ground. Some, like Prof. Roscoe (p. 387), admit, 

 when pressed, that it is a question which experience alone 

 can decide, and that they have not had that experience. 

 Liebig, to whom Mr. Gerstl refers (p. 431), was speaking 

 of a different class of schools, in which boys must pick 

 up some useful scientific facts early or not at all. Prof. 

 Henslow's experience is of the same kind. Other philo- 

 sophers, charmed with the bright intelligence of children 

 when talked to by a Faraday or a Frankland, straightway 

 pronounce an opinion on the relative value of science 

 and classics and mathematics in the early part of a 

 liberal education, — on somewhat insufficient grounds. 



The question that this discussion began with was the 

 merits or demerits of the Certificate Examination, in so 

 far as it affected science in schools. That seems to be 

 settled. We have drifted now into a different and most 

 useful discussion on the results of experience in the early 

 teaching of science. The question is this. Given that 

 boys are going to remain under a system of liberal edu- 

 cation till eighteen or nineteen, at what stages is it shown 

 by experience that it is wise to introduce the different 

 sciences ? It is a question of the comparative value of 

 different studies at different ages, not only of what may 

 best be learnt, but of what may least injuriously remain 

 unlearnt, at different ages ; and those teachers speak 

 with real weight who can institute such a comparison ; 

 men who have watched the processes by which young- 

 boys learn different subjects. A man who teaches science 

 only cannot institute such a comparison. He can only 

 say, " I do teach young boys something of chemistry and 

 botany, and they do gain something." One who teaches 

 mathematics also is so far better off that he can say, 

 " Young boys are more (or less) attentive, active-minded, 

 diligent, when they are doing arithmetic, than when they 

 are at a lesson on physical geography ; and they are 

 more (or less) incapable in later years of recovering from 

 the ill effects of neglected arithmetic than of neglected 

 physical geography." One who teaches classics also (as 

 I do for more hours a week than I teach physical science) 

 has wider grounds still for forming a comparison. 



Nothing that I see young boys do is as efficient as 

 Latin in completely occupying their minds with per- 

 petually recurring problems which tax attention, memory, 

 judgment, taste. It is quite interesting enough not to be] 

 too tiresome. The problems are easy and varied, andj 

 the solutions certain and satisfactory. The same sort ofj 

 young boys who will work hard and cheerfully over a bitj 

 of Cassar or a Latin exercise seem to be a good deal] 

 bored by a lesson on physical geography, think botanyj 

 rather nonsense, and submit silently to the hopeless unin- 

 telligibility of " matter and motion." The very same boysl 

 will as a rule enjoy an arithmetic lesson and work! 

 happily at their practical geometry, or, when well handled,! 

 their Euclid. Hence, if I wanted to train up a boy for a] 

 scientific career, I would not begin very early with science,| 

 but wait till he was thirteen or fourteen, 



I admit that the experience of some others is against me.j 



Mr. Tuckwell (p. 412) speaks warmly, and pronounces 

 my opinion to mean nothing more than that I myself 

 have failed to teach science to young boys. This is a 

 mistake. It means that I have seen the work of others, 

 here and elsewhere. It means not an absolute failure, 

 but a comparative failure, as explained above. It means 

 a summary of the opinions of a considerable number of 

 other men. Mr. Wyles (p. 455) is against me, although 

 he has " never been satisfied with his science teaching." 

 Mr. West (vol. xiii. p. 48) is against me, and his opinion 



