ideals of those who would make the laboratory train as well as inform, the notebook will contain a record of studies of animals. or plants-of actual first hand studies. It will not contain many copies of pictures from charts, lantern slides or books, for this would be information work pure and simple, and is only justified when it is necessary to fill in missing links, representing work that cannot be done in the laboratory. At most, copied work whether from drawings or from descriptions in books should form but a small percentage of the entire work. There can be no disciplinary value in it worth comparing with that obtained from actual study of the object and it is not worth while to spend much time copying such drawings just for the sake of the information. The teacher would do better either to choose a different line of work or to copy such drawings or information as he wishes himself, giving it to the pupil by means of the mimeograph.

The record contained in the notebook, then, will largely be of first hand observations. It will consist of sketches and notes. I should say practically everything studied by the pupil should be sketched. I think sketches far more valuable than notes both in disciplinary value in compelling the student to observe carefully and in faithfully recording what the student has actually seen. He may make a shrewd guess at the correct answer for his written notes, but he cannot guess where a line should be drawn in his sketch of an object; the line must go where the observer sees it or not at all. Therefore the sketches represent more faithfully the work of the pupil than the notes and are correspondingly more important.

The notes should form a setting for the sketches and should be a record of things observed. There should be as little copying of directions and explanations as possible. These are not notes, properly speaking and should not pass for such.

The manner in which the notes and sketches are prepared is very important. Our pupils are getting their first lessons in note making, hence we are responsible for the product. If the drawing made by the pupil is incorrect, it is worse than useless for it will tell an untruth to the pupil every time he sees it. Likewise incorrect notes do the same thing, but this fault does not stand out so plainly as in the case of the drawing. It is. then of the utmost importance that the sketches and notes should be carefully made. Careless, slipshod work tells nothing or little where it might tell much.

It follows that the teacher should not let any work pass which is incorrect and does not represent the very best work that the pupils can do. Of course the abilities of pupils vary greatly and likewise the quality of the work, but the teacher must hold each to his best. The poorest work can be approximately correct, so that it will not actually misrepresent the facts, though it may not be good work. Since the sketches are the most important and the notes are likely to be correct when the sketches are correct, the emphasis should be placed on this branch of the work. The teacher can very quickly inspect a drawing and they thus form the most convenient test.

It has been my experience that the drawings must be examined while they are being made so that mistakes may be corrected while the material is still before the pupil and the subject fresh in his mind. I have never found any other method effective. Merely indicating that a mistake has been made after the work has been handed in does not answer, for the pupil will usually guess at the correction needed or borrow from a classmate. Of late I have been using a rubber stamp and allow no drawing to be considered complete until I have stamped the plate "accepted." This does not conduce to absolute order and quiet, for each pupil must report with his drawing, but it is the only satisfactory method I have ever found to hold an effectual check upon careless work.

If we are to insist upon careful, accurate work in the preparation of notebooks, the notes and drawings should be made in ink. The habit of hasty scratch methods with the pencil is too strongly fixed in the pupil to be overcome. This year for the first time I have required all notes to be taken in ink in the laboratory and I have found the gain very great over any other method I ever tried. We get from our pupils just what we expect from them and insist upon. If we tell them to take their notes in ink and make no mistakes, they will be correspondingly careful. If we allow them to use a pencil, we may expect a good many mistakes. It pays to ask for the best right from the

start.

We should require that all notes be written in good English sentences, which will make sense when read in the absence of the question which the pupil is answering.

THE SIPHON-TWO NEW LECTURE DEMONSTRATIONS.

BY WILL C. BAKER,

School of Mining, Queen's University, Kingston, Ont.

The following notes are communicated to SCHOOL. SCIENCE AND MATHEMATICS in the belief that they are novel. That the experiments effectively direct the attention of beginners to fundamental points is the experience of the writer.

I. Theory of the Siphon-a lantern demonstration.

The experimental arrangement is shown in figure I where the dotted circle indicates the condensing lens of the lantern. A and B are two small beakers at different levels, containing water. Into these is placed an inverted U tube having a branch at the top as shown. A piece of rubber tubing E a couple of feet long (with a spring clip at D) enables the operator to draw the water into the tubes as in a "Hare's hydrometer." The demonstration is as follows: (a) Draw the water halfway up the tubes as shown in figure I. Call attention to the fact that the water levels in the tubes are each at the same height above their respective reservoirs; but that the difference in level of the reservoirs produces a difference in level in the tubes. (b) Draw the water up until it just flows over the bend and trickles down into the other leg of the tube (see figure II). In this state the mechanism of the transference of fluid is apparent. The atmospheric pressure tends to support water columns of the same height in each tube, but as one reservoir is higher than

the other a flow obtains. (c) Finally the water is drawn up to L (figure II), and the siphon acts quickly.

After the two reservoirs have come to the same level the removal of the block K starts the action in the opposite direction. By alternately inserting and withdrawing K, the siphon may be kept in action as long as desired. Hardwood sawdust or a pinch of black pepper in the water provides particles that are carried along by the current and indicate the flow to the class. Detailed explanation will suggest itself to any teacher.

II. Limit to the siphon's action.

T

Experiments on the above subject are seldom performed in class except in the case of the mercury siphon under the air pump. But this is not suitable for large classes and the following disposition, while not quite the same, has been found preferable.

80cm

30cm

G

G

↑

10cm

B

A tube of the form and dimensions shown in figure III has a well fitting tap at T and is bound to a light wooden frame. Two glass cylinders (GG) (graduated tubes) are filled about eleven centimeters deep with mercury and are set on blocks that hold them about ten centimeters above the lecture table. The siphon is held in a stand at such a height that the open ends of the legs are nearly touching the bottoms of the graduates, as shown. A water pump is connected to the end above T, and the mercury drawn up as far as possible. The whole system is then tipped forward until the mercury fills the whole tube below T. On removing the block sealed with about one centimeter of the fluid. When the apparatus is again set up right (and the pump disconnected), the merucy fills the whole tube below T. On removing the block B and letting the graduate stand on the table, a very rapid siphoning takes place. On replacing the block, the action re

Fig. 3

verses. If both blocks be removed the siphon will not act as the bend is now about seventy-nine centimeters above the level of the reservoirs. Thus the limit of siphoning, in the case of mercury, is actually demonstrated before the class.

By gradually raising one of the cylinders the mercury may be caused to flow across the bend of the tube and pass drop by drop into the other leg of the siphon in exactly the same manner as in part (b) of the experiment mentioned above. The comments to the class during these operations are obvious.

TUNGSTEN.

Tungsten has become of renewed interest within the last five years. owing to its wide and successful application for the manufacture of so-called self-hardening rapid tool steels. Its chief ores are wolframite, FeWO, in which some of the iron is often partly replaced by manganese, hubernite, MnWO,, and scheelite, CaWO,. The ore most suitable for the production of the metal is wolframite. Although found in many places, such as Queensland, New South Wales, Straits Settlements, Bohemia, Cornwall, Spain, the United States of America, etc., it does not occur in large masses, and is often very pockety. In the pure state it should contain over 70 per cent WO,, rendered the WO, soluble as Na,WO,, and left the tin behind, it was not until the system of electromagnetic separation was applied to those mixed ores that the problem was satisfactorily solved. The ores, whether dressed in the ordinary manner or electro magnetically separated, should be as free as possible from tin, arsenic, sulphur, and phosphorus, otherwise these impurities are apt to find their way into the metal made from them. The ore is sold on the basis of its WO, contents. At the present moment it is worth in London about 25 shillings to 27 shillings per unit of WO,thus a 65 per cent ore is worth about $425 per ton. The prices of ore have varied in an extraordinary manner; at one time it could be bought for $75 per ton, and last year it went as high as $750 per ton. With regard to scheelite, this mineral is a white heavy mineral, named after the Swedish chemist Scheele, who first found tungstic acid in the same. As it is not quite so suitable for the manufacture of tungsten metal, it has a somewhat lower value than wolframite, although, if pure, it contains well over 70 per cent of tungstic acid, not infrequently as much as 74 to 75 per cent. The world's production of wolfram ores is about 3,000 tons per annum, based on 60 to 65 per cent ore. Queensland seems to have been the chief producer in 1904, with 1,538 tons. valued at $808,175; next probably come Spain and Portugal, with about 400 to 500 tons.-O. J. Steinhart, Trans. Inst. M. and M.