то

This method requires much less recourse to the tables than the other, and is sufficiently accurate, within a square degree, on a scale of 1. The x and y may often be neglected as insensible in small projections; but no value of x, which is at all appreciable on the scale used, should be neglected. The y, for the auxiliary parallels, affects the meridian less rapidly, but its palpably sensible values should always be used.

The following quantities are sensible, yet only barely sensible, on the scales affixed:

These quantities are quite overshadowed in large sheets by the expansion and shrinkage of drawing-paper from day to day. In both methods the x and y should always be used for good projections when they would be sensible on the scale in use. And it is peculiarly essential to accurate projections that the hygrometric condition of the paper be kept as uniform as possible during all the time that measured distances are being laid down. It is often better to mark simply the intersection points by a small cross+, and to omit the remainder of the parallels and meridians. For plotted points this is also the best indication, if the cross lines are stopped on each side of the point, just far enough off to leave the dot distinct.

For drawing parallels and meridian curves, a long, slender, flexible ruler of straight-grained cedar, or other compact wood, is employed. Its cross section is three-sixteenths (%) of an inch by two sixteenths (%) of an inch. A specially designed steel ruler might be found preferable. There is a small groove on the top of the ruler, and its ruling edge is slightly beveled. Leaden, paper-covered, beak weights, of about four pounds weight each, are used to hold the ruler in place from point to point. These are so shaped as not to incommode the hand in ruling, and each has a hooked beak, ending in a knife-edge, turned downwards, which, resting in the ruler groove, throws the main bearing of the weight on the ruler, while its small end rests on the paper. The beak weights in use are five (5) inches long, two and oneeighth (2) wide, and two and one-eighth (23) deep, the beak being five-eighths (§) of an inch long, and turned down one-fourth (4) inch. The mass of lead is nearer the beak end. Having placed the ruler approximately, it is so adjusted under a beak weight to the first point that the curve will be ruled exactly through it. It is then adjusted under a second weight to the

next point, and then bent to the next in like manner, and so on until the entire curve is completed. Before ruling this the eye should criticise it carefully, as a check on graphic errors. For fine projections the hardest pencils are best; and in inking, the lines should be drawn as delicately as clearness permits.

When no metre scale is at hand, the tabulated distances can be converted into yards by using the conversion tables, or by the constants of relation between units; or, when the greatest accuracy is not important, a metre scale can readily be constructed from a yard or foot scale by proportionality. Thus, rule two parallel scales, one of yards and one of five-sixths () yards, and draw a third parallel, whose distance outside the yard-scale is 3.3685th of that between the yard and five-sixth yard scales. Through the similar graduations draw straight lines; these will give a metre scale by their intersections. If space permits, a point may be substituted for the five-sixths () yard scale. The projection once constructed, may be used independent of the unit of the tables.

ART. XXXVI.-On the Educational Uses of Museums; by EDWARD FORBES, F.R.S., &c.*

THE third Session of the Government School of Science applied to Mining and the Arts commences to-day. The Director and my Colleagues have assigned to me this year the duty of opening the courses. I shall avail myself of this opportunity to offer some remarks upon the leading and characteristic features of the Institution, considered as an educational Museum, and to make some observations upon the instructional uses to which Museums may be advantageously applied.

The school of applied sciences here established is the only instance in Britain of an organized instructional institution arising out of a Museum, and being maintained in strict connection and relation with its origin. This is not an accident, but an event contemplated from the commencement of the Geological Survey. It is an experiment on a considerable scale with a greater purpose,-for, with a limited though rapidly improving machinery, it is intended to advance educational aims that have a vital importance in their bearing on the future prospects of this country. It is an endeavor by a State-mechanism to cast the seeds of science over the broad fields of British industry,-not indiscriminately, but especially in those places where there is a good soil thirsting for their germination. We who are appointed to be

* Introductory Lecture at the Metropolitan School of Science, etc.; Museum of Practical Geology. London, 1853.

cultivators have a responsible duty and a noble task. We have firm faith in the dignity our work, and in the certainty of good results arising from it. This must be our reward; and with it we are content, as long as we can, to labor patiently and earnestly to the best of our endeavors,-hopeful of the approbation and coöperation not only of our fellow-laborers in science, but also of all intelligent and patriotic Britons.

The results so far of the teaching here have been in the main highly satisfactory. With the close of last session terminated the two years curriculum of the students who entered the Government School of Mines in 1851. Since their studies are now completed, I may speak of the men in the language not of compliment, for of that there is no necessity, but of unmixed praise. I can say this not only for myself but for all my colleagues; and we have the delightful satisfaction of anticipating a distinguished scientific and practical career for those who were lately our pupils, and whom now we number among esteemed friends. Their services are sure to be appreciated and anxiously sought for; and already we have had the pleasure of congratulating some of them on the obtainment of highly valuable and honorable posts, for which they had become qualified within these walls.

With equal satisfaction we can refer to the department of our lectures devoted to the instruction of working men. The artisans of London have eagerly and admirably responded to the opportunity so freely offered to them by Government in this Institution. They have crowded to our theatre and attended our courses with unmistakable earnestness and intelligence. address the audience, composed exclusively of working men, assembled on these benches on Monday evenings has been a privilege and a pleasure to all of us.

To

The peculiar advantages which we have held out to officers of the public service, especially to officers of the army and navy, have not been neglected by the class for whom they were intended. At the same time, it was expected that more use would have been made of them. It is difficult, doubtless, for gentlemen whose duties command so much of their time, to make days and hours suit their convenience. Those who entered our classes, have been among the most diligent of students. The majority have come to us from the East India Company's service, chiefly officers of engineers and medical officers. Much might be done for the advancement of science by naval and military men when on service abroad, and much is being done by them every day as the transactions of learned societies can amply testify. An occasional course of study in one or more of the sciences taught here would enable many a soldier and sailor to occupy vacant hours with pleasure and advantage, and possibly with benefit to the general advancement of knowledge. During the time when I had the

honor of assisting on board one of Her Majesty's surveying ships, I witnessed the happiness and profit that resulted from the pleasure taken by a corps of naval officers in scientific pursuits.

It was supposed that opportunities for scientific instruction such as are here afforded would have been appreciated by intelligent persons among the middle and higher ranks, having time at command. With the exception of a chosen few, the anticipation has proved fallacious. Possibly the occult science of table-turning, which in these days seems to occupy the place filled by astrology in days of yore, has too seriously occupied their thoughts to permit of chemical, physical, geological, or biological studies. In London there are several institutions of high character, that offer, at reasonable cost, scientific instruction to the so-called "educated" classes; yet if the numbers of all, young and old, who avail themselves of the chances that are placed within their reach were to be summed up, scanty indeed would the proportion appear who appreciate, as compared with the vast majority who neglect, the opportunity. Need we wonder then at the success of popular follies and absurdities among persons to whom, if we applied the epithet "unenlightened," we should give mortal offense? There is, indeed, no stronger argument in favor of the State taking the initiative in scientific instruction of the kind given here, than the fact, that the classes of the people who cannot afford to pay high fees, or come to learn during the hours of the day, are anxious and thankful for it; whilst those who ought to support deserving institutions of private foundation have yet to be imbued with a taste for natural knowledge, before they will do that which should be at once a duty and a pleasure.

This year our resources, though still too limited, have been considerably extended, and an important and indispensable want supplied, through the institution of a lectureship on Applied Mechanics. It is with feelings of exultation that I venture to allude to the manner in which this new post has been filled. The accession to our corps of so eminent a philosopher as Professor Willis is an honor deeply appreciated by all of us. In him we feel that we have acquired a new source of strength, whose value cannot be too highly reckoned. We feel, too, that in the world of science, and in the world of mechanical industry, the approbation of this appointment is universal.

In the presence of Dr. Hofmann, who though appointed to the lectureship on Chemistry and charge of the Laboratory, since the conclusion of last session, has sat with us and served amongst us for some time, I will not-I need not-enter on any eulogium of his distinguished merits. To have secured the services of one of the most eminent of European chemists, for the post until lately so ably filled by Dr. Lyon Playfair, is as great a satisfaction to ourselves, as it will be a guarantee of good work to the public.

His predecessor has left us for a post of heavy responsibility and inestimable importance,-one on the conduct of which the success of government institutions for scientific education will in a great measure depend. He has left us with our warmest wishes for his success, and our firmest confidence in his ability, energy, earnestness, and truthfulness. But though no longer holding a professorial post here, we retain the benefit of his advice and counsel, since he still remains connected with our institution, and sits with us as a member of our Educational Committee.

We commence the session-so far as the class of students of most consequence, viz., the matriculated class, is concerned-under peculiarly favorable auspices. The number of entries is greater at this early stage of the courses than during either of the former years. Considering how difficult it is in our country for any establishment on a new plan to make way, this evidence of progress may be taken as a fair subject for congratulation.

The object of the Museum in which we are now assembled is mainly the illustration of the mineral constitution and products of the British islands, and to some extent, of the British colonies. This purpose, whether we consider the great benefit derived from mineral wealth by our nation at large, the vast capital invested in the search after and application of mineral resources, or the light thrown upon science under its nobler and less profitable forms, cannot but be esteemed a worthy one. To carry it out effectively would require more than double the space here assigned to it, and powers of speedy and comprehensive action such as are not usually conferred upon the managers of State institutions. The purpose of the place in some of its branches is more or less fully presented, but in others is barely sketched or rather indicated. The applications of mineral products to the various useful and ornamental arts are so numerous, that, except in a few principal instances, it would be folly to attempt their illustration within our confined boundaries. Consequently, in a purely industrial direction our display is sketchy and partial. That a collection fully and judiciously illustrating the arts that spring from the world of minerals, treated with equal regard to their present extension and past history, to their excellencies, capabilities, and defects, would be in the highest degree instructive and beneficial, if employed in the illustration of well-devised courses of instruction, there cannot be a doubt. If ever such a collection be formed, this institution may fairly claim the credit of its paternity.

In one of its departments this Museum aims at more amplitude; and even proceeding at our present somewhat tardy pace-inevitably so, as we are situated,-must in the end attain, or at least nearly approach, completeness. I allude to that devoted to the illustration of the geological structure of the British Islands. You are aware that we are here an establishment in intimate connex