Sidebilder
PDF
ePub
[ocr errors]

should compare those of his own making with the measures of the grocer. If the teacher can have a set of boxes made of glass or of metal, he may at once proceed to find the relation between volume and weight; otherwise he will be obliged to take on authority the facts about to be stated.

The first box will contain exactly an imperial pound of water at the English normal temperature and atmospheric pressure, (60° F., 30 in Bar.) It will also contain of any liquid or solid the number of pounds represented by its specific gravity, e.g., Alcohol, 0.85; Mercury, 13.6; Sulphuric Acid, 1.84; Platinum, 21.5.

The second box may be associated with a very interesting series of facts. It will contain one grain of Hydrogen, and of other gases and vapors, weights in grains corresponding to their atomic weights, or some multiple of them, as is represented in the following table which is worthy of careful attention. Consequently, if we reckon their specific gravities from hydrogen as the standard, the same numbers or multiples will express these also. In many cases the atomic weights, weight in grains, and specific gravities are denoted by the same numerals:

a

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][ocr errors]

9 17 2

Ammonia ........ 17

8.5

42 This box is 1.6798 times larger than the water-pound box, and is capable of containing 11758 grains of water, or 252797 grains of Platinum. These numbers will, therefore, represent the relative weights of equal volumes of Hydrogen (1), Water, and Platinum. Conversely their reciprocals will represent the relative volumes of equal weights of these substances, Hydrogen being 1. A small cube 0.158 inch on each side will equal the bulk of a grain of water, and another, 0.057 inch on each side, the bulk of a grain of platinum. For the sake of comparison, let the pupil make two such cubes of wood, chalk, or some other easily wrought material.

If the time can be spared for this exercise, the pupil may increase the number of his cubes of grain-volume of various bodies. Box No. 5 would form one of the suite. He can readily calculate the size of one grain of each of the elements, from that of the Hydrogen grain, or from the grain of water, which is .003961 cubic inch. So also pound-volume boxes for solids and liquids can readily be calculated and made for comparison with water and with each other. Of course, it would be out of the question to include gases in the pound-volume suite, inasmuch as the hydrogen pound box would be about 69 inches on each side. Pound cubes of many solids, as lead, wax, wood, zine, etc., etc., which can easily be made or bought, possess many advantages for reference on account of their permanent form. The pupil can cast easily fusible bodies in wooden boxes coated with graphite. The casts should be made a little larger than needed and filed to size.

The litre box is a decimetre on each side (3.9370788 inches), and contains one thousand grammes = one kilogramme

= 2.2046 lbs. avoirdupois = 15434 grains of distilled water in vacuo at 390.38 Fahr. Its volume equals 1000 cubic centimetres imperial pints. The volume of one pint may be indicated by drawing a heavy line 2.236 inches from the bottom. The size of this box furnishes an excellent starting point for preparing kilogramme suites as just recommended for pounds. With water as the standard, it will contain as many kilogrammes of any substance as are denoted by its specific gravity. Hofmann proposes to make it also the standard volume for gases and vapors, and to call its volume weight of Hydrogen one Crith = .0896 gramme=1.383 grains. If we adopt the crith as the unit instead of the grain, all that has been said of the second box with reference to the relation between atomic weights, absolute weights, and specific gravities applies to this box, with the interchange of the terms grain and crith. But with the same volume as the standard of comparison for all bodies, it becomes necessary to have one suite for gases and another for liquids and solids, and also to bear constantly in mind the ratio (11758) between the two standards, water, and hydrogen. If the reader has never seen a litre measure, he ought to make one in order to obtain a correct notion of its size by actual sight and experience.

= 1.763

The 100 inch box is frequently mentioned as a unit of volume, deriving its sole importance from this fact. It contains of Hydrogen, 2.14 grains; Air, 31.074 grains; Water, 25245.6 grains = 3.604 lbs.; Iron, 28.11 lbs.; Platinum, 75.68 lbs.

It is a matter of greater difficulty to make our pupils familiarly acquainted with weights by their actually handling them. Nevertheless something may be done even in this direction. The volume boxes have all been constructed with reference to weights, and from them, with a little imagination, the pupil can conceive how large a specified weight of a given substance would seem, if he can not imagine how it would feel. His strength will not permit him to acquire a wide range of personal experience in judging the weight of bodies by lifting, but he may learn a few of the more common units.

The teacher may now bring his balance into use, and exercise the pupils in guessing weights of objects near at hand, as books of different sizes, chairs, etc., etc. A profitable variation of guessing weights, is to require each pupil to put into a bag a certain weight of sand or shot. We all know how nearly grocers will estimate a desired weight of merchandize, although they are generally guided in their guess by the bulk of the articles. So also it is well to encourage the pupils in guessing the weight of objects solely by the size, as heaps of hay, live animals, etc., even if it is not possible to give them practice in examples of this sort at school.

But after all we have said as to what may actually be accomplished in the class-room, it must be borne in mind that the chief utility of this kind of work, is the quickening of the observation, and the possible formation of a habit of estimating the size and weight of familiar objects. If these ends are attained, the exercise becomes trebly profitable. Much must be left to the discretion and invention of the teacher. The questions of proper time and place, and of suitable objects, must be settled each for himself.

These notes do not aim at any thing higher than offering a few general hints of special themes, with the hope that some one after putting them in practice, and, reviewing them as occasion permits, will be so far profited thereby and interested as to commend a similar course to his fellows.

8. A. N.

PROFESSOR YOUMANS ON THE CULTURE DEMANDED

BY MODERN LIFE.*

A matter so vast and grave as that suggested by the title to this volume,'can not be adequately considered by any individual mind. The word Culture, in the broad sense here indicated, involves such training of specific faculties, such adjustment and combination of mental powers, such impartations of stimulating and nutritious knowledge, such growth and maturing of all that contributes to make man an intellectual and moral being, that it may well be questioned whether any single thinker could give the term a just and adequate definition. So the added phrase, Modern Life, implies so much in relation to the present state of the globe, and to the present position of man and of society, suggests such wide, complicated, profound inquiries into the mental and social and civil and religious condition of mankind wherever civilization exists,—that he who should attempt to describe just what type of culture would meet the demands of this multiform life, and make the most of man and of society exactly as they are, would soon find that he had undertaken a task to which no individual mind is competent. It is only by the joint contributions of many cultured and earnest inquirers-by the confluence of many tributary streams of thought and of investigation—that such a problem is even partially to be solved. Yet we are none the less to encourage individual thought, or to welcome whatever any intelligent lover of culture may desire to say on this vast and weighty theme,-assured, as we are, that each and every such effort, rightly received, will furnish some desirable impulse toward the ultimate solution.

It is no harsh criticism to say, that this volume can not be regarded as a broad, calm, thorough discussion of the theme indi. cated in the title. So much of it as was written by Professor Youmans, is rather a somewhat narrow and partizan presentation of the claims of scientific as opposed to classical education; and the various addresses and essays that compose the main portion of the volume, are devoted to the commendation scientific studies, rather than to any comprehensive consideration of the culture demanded by modern life. After admitting all that is claimed by the editor of these essays and addresses, or inculcated

* THE CULTURE DEMANDED BY MODERN LIFE. By Prof. E. L. Youmans. Pp. 473. D. Appleton & Co. 1867.

by the series of eminent witnesses whom he summons upon the stand, the thoughtful reader must perceive that the problem suggested in the title is still far from being solved ; and that, beyond any possible controversy between the advocates of classical and the advocates of scientific training, there is very much in this great matter of culture which is worthy of most careful examination. It may, indeed, be questioned whether the exciting or the prosecution of such controversy does not tend to obscure our vision of the true problem to be solved; and whether more broad and just views of culture would not more readily prevail, if the advocacy of such specific methods of training were for the time suspended.

Partizanship is extremely liable to be disingenuous and even unjust; and the editor of this volume can hardly claim to have altogether escaped the common liability. To say nothing of the disposition to stigmatize the advocacy of classical education as inspired by an excessive love of tradition or by mere regard for caste, or as willfully indifferent to the issues of such education, or the larger benefits accruing from scientific studies, it may be seriously questioned whether Professor Youmans has not sought to strengthen his own position by putting the eminent authorities whom he quotes into attitudes which they never intended to occupy, and by using them in ways to which some of them would never have consented. The address of John Stuart Mill, taken as a whole and read independently, would probably make upon no one the preoise impression made by those portions of it quoted in this volume, and set in such peculiar collocations. The lectures of Whewell and Faraday and Liebig, and others here published-delivered as they were on various occasions and for the most part independently of each other-were not designed to be used as so many parts or sections of one vast argument against classical training; and it is quite doubtful whether all of these distinguished authors would have consented to any such use. The same criticism is applicable to some at least of the minor quotations published in the appendix. It surely is possible for men to commend the study of botany or zoology, or to advocate a more general interest in scientific education, without condemning the pursuit of classical studies or undervaluing the influence of linguistic culture. Antagonism to Greek and Roman literature is by no means a necessary consequence of devotion to physiological or to social science; nor is it to be taken for granted that every friend of such sciences is ready to sustain Professor

« ForrigeFortsett »