NO-NaNO: (sat.) +[HC1 (dil.)+FeCl2]+heat N- NaNo (sat.) +[NH.Cl+H2O] +heat. SO-HC1 (dil.) +Na H SO1 CH1—[C:H2OH (absolute)]+H2PO. (173) H Br-Br: [(red) P +HO] The first chemical in each of the above list used for generating the gas should be in the dropping funnel and those following should be in the Erlenmeyer flask. It will often be found desirable to use this apparatus for generation of CO2, H and HS in preference to the ordinary Kipp apparatus. For lecture work a Kipp has the great disadvantage that one is unable to know whether it may not become exhausted during the time for the lecture. Consequently rather than take chances a Kipp should be refilled very frequently with much loss of good acid. FIG. 3. OSMOTIC PRESSURE TUBE. This tube (Fig. 3) is made from barometer tubing about five feet long, with an enlargement and stopcock as shown by drawing. A parchment tube made by Carl Schleicher and Shull (No. 579 Diffusion Hulsen size 100x16 mm.) is fastened on the lower end. This may be made tight to the glass by applying a soft wax or a stopcock grease on ends of both parchment and glass tube and tying after many turns by strong linen thread; and then by means of a cork borer slightly larger than either tube, a short rubber tube may be stretched over the joint. The rubber tube should be stretched over the cork borer (or a simi lar brass or glass tube); then with safety it may be brought over the parchment tube and slipped from the cork borer onto the junction of this tube with the glass. When this is done a leak is very improbable, even though the solution may run over the top of the barometer tubing. By means of the stopcock a strong sugar solution, which has been colored by some red dye, may be introduced. The parchment tube then being placed in water in a beaker, the sugar solution will rise rapidly owing to the small bore of the barometer tubing, and the large surface of the parchment. The barometer tubing however magnifies the bore and the red solution may be observed at a distance by a large class. By allowing the parchment tube, after rinsing out sugar solution, to stand in a bottle of water, the whole apparatus may be kept intact and ready for use for a long time. The first one made did not need the parchment tube renewed for eighteen months and was used probably on the average once per month. This makes very easy a lecture experiment, otherwise difficult because of trouble of preparation and danger of leaks. The total production of crude petroleum in the United States in 1905 was 134,717,580 barrels, as against 117,080,960 barrels in 1904, 100,461,337 barrels in 1903, 88,766,916 barrels in 1902, and 69,389,194 barrels in 1901, an increase of 17,636,620 barrels, or 15 per cent over the production of 1904, and of about 34 per cent over that of 1903. The increase in 1904 came from Kansas and Indian Territory, and Oklahoma, Louisiana, Texas, California, Kentucky and Tennessee, and Illinois, in the order named. In round numbers, the gains in 1905 over 1904 were as follows: Kansas and Indian Territory and Oklahoma, 6,395,000 barrels; Louisiana, 5,950,000 barrels; Texas, 5,890,000 barrels; Kentucky and Tennessee, 219,000 barrels; and Illinois, 181,000 barrels. The largest decreases in production in 1905, as compared with 1904, were in Ohio, which showed a decrease of about 2,529,000 barrels ; West Virginia, 1,066,000 barrels; Pennsylvania, 688,000 barrels; Indiana, 374,000 barrels; and Colorado, 125,000 barrels. It will be ob- . served that the greatest gains were in the South and West, and that, relatively, the Appalachian field lost heavily. The value of crude petroleum produced during 1905 was $84,157,399, or an average price of 62.47 cents a barrel, as against $101,175.455, or 86.41 cents a barrel in 1904, as against $94,694,050, or 94.26 cents a barrel in 1903.-U. S. Geol. Survey Bulletin 260. *All of the above glass apparatus may be secured from W. J. Boehm, glass blower, 171 Randolph Street, Chicago, Illinois. STANDARDS IN SCIENCE TEACHING. BY FRANKLIN T. JONES. University School, Cleveland. The standard each teacher sets for himself and his pupils is necessarily a local one-reasonable under the conditions under which the work is done. This paper has to do with some of the standards and devices for enforcing them which have proved useful in my own teaching and with some general principles which could be successfully applied and would result in much greater uniformity in science teaching. My pupils must be prepared for the examinations for Harvard, Mass., Inst. of Technology, Yale, Princeton and Case School of Applied Science, and I have been compelled to study their requirements as illustrated in past examinations very carefully. At the beginning I had the same distrust of the fairness of the questions which is shared by most teachers who have not studied them systematically. It is true that every now and then unreasonable questions slip in but, on the whole, the questions are fair and not too difficult. In a surprising way they pick out and emphasize the real fundamentals of the subjects covered. I have cut up old papers and mounted the individual questions on cards which have been classified and arranged as a card catalog. In the course of the year each student works through the list, if possible three times-once as the subject first comes up in the year's work, once again in the review at the end of the year, and out of this list I have selected about 300 problems and questions in physics and about 200 in chemistry which I use as a final review to clinch not only the facts of the subject but also to emphasize the fundamentals which every pupil understands he must know. The fact that the questions are from bona fide examination papers compels a respect which the ordinary problem rarely receives; then too a student takes greater pride in producing satisfactory answers to such questions because he believes in the college examinations as setting a high standard. The effect of such a standard upon the teacher is very marked. He is compelled to work out the important points with great care and almost instinctively gives to the less important their proper emphasis. He differentiates between the essentials and those things which are only introductory to the essentials in a way of which he never before dreamed. The economy of time is tremendous, amounting to fully one-fourth in the course of a year. Formerly I used to get one month at the most for reviews at the end of the year. Last year (1905-6) I had two months in physics and three in chemistry. This year I hope for about three months in each subject. This time may seem disproportionate for review but a trial will prove the wisdom of the practice. More real learning will be done in the last two months than in the whole preceding work of the year. A many-sided review is an essential point in the maintenance of a high standard. I aim to cover the whole subject three times in the review-once from the historical point of view immediately following the completion of the advance work. At that time the student can see a man's discoveries in their relation to the whole subject and understand him as he could not earlier once by questions for definitions, laws and principles in physics, and in addition for equations in chemistry; the third time by means of college examination questions and problems. If any student has honestly gone through such a course, one need have little anxiety about his knowing the subject so thoroughly that he is ready for any examination, not because he has been crammed for the occasion but because he has mastered the subject. They are primarily to blame by not We hear complaints from the colleges about the preparation we give our students. setting the standard at the proper quality of work. The quantity demanded is in most cases unattainable without sacrifice of quality. If all the colleges in the country would require entrance examinations of a reasonable kind-and, in the sciences, the examinations of Harvard, M. I. T., Case, Yale, Princeton and the College Entrance Examination Board are not unreasonable-we need be far less concerned over our standards in science teaching. An immediate objection to a standard thus set by examination is that for the satisfactory answering of the examination questions. If the average set of questions as asked by Sheffield Scientific School or Princeton in physics or chemistry is taken as the list for our teaching will degenerate into cramming our pupils which preparation is to be made, cramming will result in an immediate improvement in the efficiency of our instruction approximating 25 per cent. To those who make a study of the questions the reasons for improvement will become at once apparent. Fundamental things are asked for and real preparation for such questions will necessitate a thorough mastery of basic principles-not only an understanding of them but the ability to express them in clear, concise, accurate English. This ability can be acquired only by practice. In my own teaching I find great difficulty in getting satisfactory written answers on simple fundamentals like the parallelogram of forces and its applications even though they are harped upon from beginning to end of the year. I believe the solution of the difficulty lies in repetition-in frequent rewriting of the answers to questions which involve these principles. An essential in the enforcement of a high standard is the avoidance of too difficult questions and problems early in the year's work. The main reason for the almost universal repugnance with which physics is regarded is the unattractive way in which the subject is as universally introduced. Any subject which necessitates hard study and prolonged and consistent effort must be carefully handled at the outset so as to prevent the development of prejudice and the consequent excuse that it is too difficult for the average student. The preliminary steps in chemistry may be taken rapidly but the opposite is true in physics. I doubt if the first ten lessons in physics can be made too easy. Each pupil must be convinced that he not only can but almost likes to do the work prescribed and, as the course progresses, no precautions are too great to make sure that he solves all the easy problems given. From simple beginnings the teacher can work up the ability of his pupils to the point where even the difficult problems from the college examinations are possible. The critical point is never to impose a task that the pupil with reasonable effort cannot perform-to encourage by the consciousness of growing ability, not to discourage by assigning work that the pupil can not be expected to do-and finally to insist upon the satisfactory completion of the lessons given. Another objection to be raised is that questions of the kind proposed will make our work mechanical and tend further to impair that "human-interest" about which so much has recently been written. I think it is sufficient to call attention to the fact that the humanizing of any subject depends, as we can all testify, not upon text-book nor syllabus nor method but upon the teacher. In his power lies the vitalization or devitalization of the subject taught. |