390 



NA TURE 



[Fed. 



1888 



aim of science. Jt is impossiiile to estimate the good thnt might 

 be done in this direction, if only the Universities had the wisdom 

 and the courage to insist upon a knowledge of some one branch 

 of science for all degrees, as was strenuously advocated years ago 

 by Charles Kingsley. 



(3) It seems a great pity that such a change as is contemplated 

 should be adopted just now, since within the last three or four 

 years some of us who are teachers of standing and experience 

 have gladly recognized considerable improvement in the 

 examinations in science as they are conducted by the Civil 

 Service Commissioners. It would appear that the (ramming of 

 these subjects has been considerably handicapped, if one may 

 judge from the considerable increa^^e in the number of o's 

 affixed to the names of candidates in the published lists pari 

 passu with a considerable increase in the number of marks 

 gained by one's own pupils, who have had the same teaching 

 and laboratory ti^aining as those of previous years. 



(4) It is surely fairly within the provinca of Parliament to 

 consider the question whether it is expedient or conducive to the 

 common weal, that science shall be placed at such a dis- 

 advantage that young men, who are candidates for the more 

 scientific branches of the military service, shall be strongly 

 tempted to eschew all preliminary training in science, as they 

 certainly will be unless the regulations are somewhat modified. 



Four years ago the action of a single Member of Parliament 

 (Sir John Lubbock), backed up by the influence of the Councils 

 of the Royal Society and the British Association, was effectual 

 in securing a reconsideration of the provisional examination 

 scheme for admission to Sandhurst ; so that, although — as ulti- 

 mately issued — the regulations contained an absurd anachronism 

 in the proportion of marks assigned to scientific subjects, this 

 was reduced to less startling proportions. 



Can it be doubted, then, that if on the present occasion the 

 three Members of Parliament who may be said to be the 

 representatives /ar (?jr(r^//^«<r£ of science in the Legislature (the 

 President of the Royal Society, the President of the British 

 Association, and the Member for the University of London), 

 were to take united action in Parliament, the position of science 

 (so far as the Army Entrance Examinations are concerned) might 

 be changed from one of semi -strangulation to one of free and 

 fair competition, which is all that its most ardent advocates can 

 desire for it ? This could be effected to the advantage of the 

 studies of the cadet, by such a simple modification of the pub- 

 lished regulations as would be involved in limiting the choice of 

 optional subjects in Class I. to two, and allowing two subjects of 

 Class II. to be taken up. A. Irving. 



Wellington College, Berks, February 20. 



The Composition of Water. 



Prof. Thorpe, in his interesting article on the composition 

 of water (p. 313), alludes to Dr. Scott's very valuable determina- 

 tions of the ratio of the volumes of hydi'ogen and oxygen which 

 combine to form water. 



If we assume with Dr. Scott that the small amount of im- 

 purity present in his gases, and which he estimated in each case 

 after the explosion, was evenly distributed between them, a 

 curious relation may be observed between the amount of impurity 

 present and the calculated ratio of the volumes. 



This relation is apparent if we subtract the ratios calculated 

 by Dr. Scott from some fixed number, say 2"000, and compare 

 these differences with the relative amounts of impurity. It will 

 be seen from the following table that the greater the amount of 

 impurity present the greater is the difference of the ratio from 

 the constant number, or, in other words; the lower is the ratio. 

 The impurity is given in volmnes per 100,000, and the differences 

 are multiplied by 10,000. 



The relation is better seen, however, by mapping the results, 

 taking the ratios as absciss^^, and the impurity in volumes per 

 100,000 as ordinates. The dotted straight line (Fig. i) passes 

 so well through the points that it leaves ten of them on the one 

 side and eleven on the other. 



It seems difficult to believe that this apparent relation can be 

 merely a chance coincidence ; the direction taken by the points 

 is too definite . Nor can it well be due to any chemical action 



Bwm ■■■■(!■■■■■ 

 ■r/BL «■■■■■■ 



■■■ ■■■■■»■!! 



Fig. I. 



between oxygen and nitrogen, for Dr. Scott states that the water 

 produced was free from any acid reaction, and that no trace of the 

 oxides of nitrogen could be detected. The relation is even 

 more marked if we assume that the whole of the impurity was 

 in the hydrogen. This is shown in Fig. 2 ; the points obviously 

 fall about a line which is nearly, if not quite, straight. 



Fig. 



If, however, we assume that the whole of the impurity was in 

 the oxygen, and if we neglect the two experiments with the 

 excessive amount of impurity, no such relation is to be observed 

 (see Fig. 3), but the ratios are distributed with fair regularity 

 about a mean value of I-9965 or 1-9970. The simplest ex- 

 planation of the facts appears to be that the whole, or at least 

 the greater part, of the impurity was really in the oxygen, and 

 that the apparent relation of the amount of impurity to the ratio 



