German air-nitrate factories are situated. A process has been discovered by which nearly twice the usual amount of ozokerite can be obtained from lignite, and the gas is being more extensively used for heating and smelting purposes.

Nature reports that one of the great captains of industry of Scotland has specially organized and equipped an engineering factory for the employment exclusively of educated women of good social standing instead of the usual woman factory worker, and with the fixed determination to carry on operations permanently under those conditions, the work to be taken up being that associated with the manufacture of internal-combustion motors. There is a fully illustrated account of the new factory in Engineering for November 9, from which it appears that it has some of the salient feature of a technical college combined with practical work in the factory, which gives that stimulus to study not realizable in the laboratory of a college. The factory is situated in the south of Scotland amidst beautiful scenery, so that students of botany and of wild-life generally can have full opportunity of pursuing their hobby. All the accessories which are now placed under the wide term "welfare" have been adopted to the fullest extent. Highly trained lecturers conduct classes at the works; these are compulsory. Entrants receive 20s. per week during the probationary period of six weeks; they then decide whether or not they intend to pursue the engineering career. If such be the case, and they are considered suitable, an apprenticeship agreement is entered into, and the wages become 25s. per week. Examinations are held at six months' intervals, and each "pass means an increase of 5s. per week. It is evident that the whole scheme provides for women the opportunity of prosecuting an engineering career under the most favorable and stimulating conditions, and that the conditions are those best calculated for women of good education and social standing to attain a broad experience of engineering science and practise.

WE learn from the British Medical Journal that the Army Council has issued an instruction providing that students who at the time

of their enlistment (whether they enlisted voluntarily or were called up under the military service acts) were actively engaged in medical studies and had completed the second year of their professional course, are, if eligible, and they so desire, to be transferred to the reserve, or discharged if ineligible for transfer to the reserve, for the purpose of resuming their studies with a view to obtaining a medical qualification. For the purpose of this instruction a man who had on or before enlistment completed two years of medical study, and who can within thirty-six months complete his professional curriculum and obtain his medical degree or license, is to be regarded as a third-year medical student. Students who do not pass the professional examination in anatomy and physiology within six months of resuming study will be recalled to the colors, and a student transferred to the reserve, unless he resumes his medical studies and enrolls in an Officers' Training Corps, will be recalled. Any third-year medical student who is desirous of being released from the colors under this instruction must apply through the usual channels, stating the date on which he desires to be released, and that he undertakes to resume his studies with a view to obtaining a medical qualification. A similar difficulty is being met in a different way in France. Owing to the prolongation of the war the supply of newly qualified men is drying up; casualties among medical officers have been numerous, the medical service in this respect coming next after the infantry. The French mobilization scheme provided that a medical student in a certain stage of the curriculum, reached usually at the end of the second year, should, when called up, be appointed médecin auxiliaire, a grade unknown in the Britsh army, but corresponding with that of surgeon probationer in the Royal Navy, which itself is the revival of the old grade of surgeon's mate. The case of medical students who have not advanced so far has recently engaged the attention of the Ministers of War and of Education, and of the General Staff, with the result that arrangements have been made by which medical students from the ranks may attend special courses of lectures

and eventually obtain credit for them when they seek a civil degree in medicine. Three schools of military medicine have been established for their benefit in regions behind the front, and have been duly provided with professors, libraries and laboratories.

UNIVERSITY AND EDUCATIONAL NEWS

REACHING a total of $515,436.09, federal grants of money to seventeen states under the Vocational Education Act were allotted at the meeting of the Federal Board of Vocational Education on December 21. Each of these states has complied with the terms of the law and has agreed to match every federal dollar with money publicly raised by the state or local community. The states are as follows: Alabama, Colorado, Florida, Iowa, Kansas, Michigan, Minnesota, Mississippi, Montana, Nebraska, North Carolina, Ohio, Oregon, South Dakota, Texas, Washington, Wyoming.

ACCUSATIONS of disloyalty against five members of the faculty of the University of Illinois were found on December 11 to be without grounds, by a subcommittee in a report to the board of trustees of the institution.

PROFESSOR G. H. SCOTT, for fifteen years professor of mathematics and astronomy in Yankton College, Yankton, South Dakota, has resigned to become principal of Benzonia Academy, Benzonia, Michigan.

FRANCIS W. KIRKHAM, of the Brigham Young University, has been chosen director of vocational education for Utah, following the laying of plans to bring the state under provisions of the Smith-Hughes act.

DR. WRIGHT A. GARDNER, formerly associate professor of botany and plant physiologist at the Idaho University and Station, has been appointed plant physiologist and head of the department of botany at the Alabama College and Station.

DISCUSSION AND CORRESPONDENCE A SUGGESTION FOR STAINING TECHNIQUE WHERE one has many slides of sections passing through the various stages of dehydration and staining, a systematic method

of labelling must be followed. Suggestions have been made to do this by means of a diamond point pencil or waterproof ink.

Neither of these methods have worked satisfactorily for me the first being too difficult to perform rapidly even after a good point has been procured and the marking being very difficult to read when covered with a dark stain. The second has these disadvantages and in addition the marking is very liable to rub off.

Therefore I suggest the following method which has worked satisfactorily for me while staining hundreds of sections at a time. Small aluminum clips with a numeral stamped or stencilled on each were prepared. These clips fasten on the edge of the slide when in the staining jars and are not large enough to prevent placing a cover on the jar. The data may be written in whatever manner desired in a notebook with the number or character to correspond to that on the aluminum clip. These clips are cheap, may easily be made and very few reagents ever used in dehydrations or staining attack the aluminum. The same clip may be used repeatedly.

TOLEDO, OHIO

PAUL ASHLEY WEST

A NOTE ON THE PREPARATION OF SKELETONS BY BACTERIAL DIGESTION

THE method of preparing skeletons by bacterial digestion is of long standing and has given excellent results. The present modification of the method was devised to obviate two objections which are of considerable importance when skeletons are prepared by students as class work. First, the digestion mass produces a foul odor and is disagreeable to handle, and, second, the digestion process, unless carefully controlled by frequent examinations is likely to result in displacement and subsequent loss of the smaller parts of the skeleton.

These objections are to a large extent overcome by embedding the roughly cleaned skeleton in a solid medium supporting bacterial growth. Agar-agar is preferable to gelatin, since it is not liquefied by the common bacterial enzymes. The method is as follows:

The skeleton of a freshly killed animal is more or less carefully cleaned of muscles and embedded in a plain agar solution (15 gm. per liter of water) which has been cooled to the pouring temperature (43° to 45° C.). The medium is allowed to solidify and the preparation is covered and set away at room temperature. The digestion requires from ten days to several weeks, depending largely on the extent of the preparatory cleaning. The time may be reduced by the use of incubator temperature. We have tried inoculating the skeletons with cultures of anaerobic proteolytic bacteria, but without great advantage.

The medium absorbs much of the odor and with suitably covered dishes it has been possible to leave the cultures standing in the laboratory. When the digestion is completed the bones can be conveniently dissected from the medium in their original relations. Washing the parts as removed completes the process. The skeletons thus prepared are very white, and bleaching is usually unnecessary. The method is best adapted to small skeletons, which can be embedded easily. It is these, however, which present the greatest liability to loss of parts in a fluid medium. The method promises to be particularly useful in the study of the cartilaginous skeletons of embryos. RALPH G. HURLIN

BIOLOGICAL LABORATORY, CLARK COLLEGE

SHALL THE USE OF THE ASTRONOMICAL DAY BE DISCONTINUED?

TO THE EDITOR OF SCIENCE: The question has recently been raised in England whether the astronomical day should not be set back twelve hours, so as to begin at midnight instead of at noon. It is stated by those advocating the change that the practical consideration of those using the Nautical Almanacs should prevail as against the usage of astronomers. The opinion of American astronomers has been requested and a committee of the American Astronomical Society has been appointed to collect information for presentation at the next meeting of the Society.

The committee desires to obtain an expres

The Microscope. By SIMON HENRY GAGE, Professor of Histology and Embryology, Emeritus in Cornell University The Comstock Publishing Company, 1917. Twelfth edition, 472 pages, 252 text figures.

This standard work is so well known to American students that extended comment upon its usefulness or upon its special merits is superfluous. The twelfth edition has been more extensively revised and rewritten than any one of the earlier ones. While many new things are presented, nothing has been considered which the author has not personally tested and found practical. Among the more important new devices described are: (1) the single objective binocular for both high and low powers; (2) improved apparatus for drawing with the projection microscope; (3) perfected ray filters which make it possible to get photomicrographs of almost any microscopic specimen; (4) the use of "daylight" glass in microscopical illumination, and (5) the dark field illumination for all powers which makes it possible to study living structures in much greater detail than heretofore. Some subjects treated in the previous edition, such as metallography and microchemistry, which are now presented adequately in other available works, have been omitted. Because of its clearness and accuracy of statement, its well-chosen material, and its wealth of information, the book will without doubt continue to be the most widely used volume on the microscope in American laboratories.

M. F. GUYER

Introduction to Rural Sociology. By PAUL L. VOGT. D. Appleton and Co., New York. 1917.

This book was written primarily as a text for college students interested in the social problems of small communities. The subject matter is what one would expect in such a book. The physical basis of rural life; the rural population, its movements, its health and its attitudes of mind; farmers' organizations, both social and economic; the established institutions dealing with country life, e. g., the church and the school; and the relation of the village to the open country are the principal topics discussed.

Throughout the book it is very apparent that the author has been at great pains to make his work as accurate and comprehensive as possible. In both respects he has succeeded admirably, and that, too, without becoming tedious. In fact, I think the combination of the essentials of a text with a pleasing exposition will recommend the book to a rather large circle of readers outside of the class room.

A feature of the book especially worthy of notice is the thorough discussion of the relation of the village to the life of the open country. The author fully realizes that there can be no satisfactory development of agencies for the betterment of rural life unless village and farm cooperate and he has expressed this view clearly and convincingly.

No doubt reviewers will always feel that sins of omission are frequent. I am happy to say they are but few in the work under discussion. To my mind the most important omission is the failure to discuss the eugenic problems of the rural population and to give more attention to the natural movements of population due to the varying birth rates and death rates in different groups and in different sections of the nation.

In the numerous suggestions for the improvement of rural life occurring in almost every chapter the author shows sound practical sense. He knows rural communities at first hand. He knows their prejudices, their apathy, their strength and their weaknesses.

One feels that the spirit of the writer would go far towards allaying the suspicion and the hostility so often encountered by those who would help to make the rural community a better place to live.

WARREN S. THOMPSON

UNIVERSITY OF MICHIGAN

SPECIAL ARTICLES NOTE ON A WET CONDENSER SUITABLE FOR CONTINUOUS HIGH POTENTIAL SERVICE

IN certain investigations necessitating long continuous production of a fat spark by means of a closed circuit transformer (1 K.W., 110 v. primary, 11,000 v. secondary) it was found that the glass plate condensers usually provided for this purpose repeatedly broke down owing to the heating under continuous performance. It occurred to us to substitute the ordinary glass with some glass having greater heat-resisting properties.

One liter, tall form, lipless "Pyrex" beakers were accordingly covered with tinfoil as carefully as possible, both on the inner and outer surfaces. These were then mounted by placing the edge into a groove in a board and sealing in with rosin. Condensers of this kind were tedious to make, and proved quite a problem to mount securely. The labor involved in producing a producing a set of the required capacity stopped work in this direction.

The final form of condenser which has proved very serviceable for the work in hand was that in which the "Pyrex" glass beakers mentioned above constituted the dialectric, and a nearly saturated solution of common salt constituted the conductor plates. The beakers were filled to within 2.5 cm. of the rim with the solution, and were immersed to a similar depth into the solution contained in an earthen vessel, a 3 gallon crock. The beakers measure 9 cm. in diameter, 19 cm. high, 16.5 cm. effective height, thickness, about 1.2 mm. The twenty beakers used were selected from a stock of about 100 in order to avoid flaws, particularly bubbles. The stock was a little old and therefore probably not as good in evenness of surface and homogeneity of material as that now being manufactured. It was not pos

sible to avoid such defects entirely, but it is interesting to note that no beaker has proved defective after very long and severe use.

The place subjected to greatest danger of puncture and that which allows greatest leakage is where the exposed surfaces of the solution inside and out come in contact with the surface of the beakers. This defect can be reduced considerably by filling the beakers with the salt solution to a slightly different level from that of their containers. Care should be taken not to wet the portion of the beaker that is not immersed. To eliminate sparking quite completely, however, the surfaces of the solution inside the beakers and that surrounding the beakers were covered with a layer of oil 5 cm. deep. For this purpose a 300-degree mineral seal oil was used. This oil, as Mr. C. E. Skinner kindly informed us, has very good dialectric properties as good as can be expected from an oil not free from water. Whether this layer of oil eliminated sparking at the sacrifice of some capacity we have not determined.

The capacity of these condensers was estimated by the method of divided discharge and by the method of mixtures. The capacity of each of the five jars containing four beakers each was: .0088 M.F., .0091 M.F., .0093 M.F., .010 M.F., .0088 M.F. respectively. The mean of these capacities is .0092 M.F. A similar estimation of the capacity of two such beakers covered with tinfoil indicated that their combined capacity was very appreciably less than two beakers of the wet condenser. This is probably due to the unevenness of the surface and the difficulty of making contact between the glass and the tinfoil.

A comparison was made between the wet condenser as above described in which beakers of Jena glass and of "Pyrex" glass were used. The dimensions of these beakers were approximately the same. Assuming that the average thickness of the "Pyrex" beaker is equal to that of the Jena and assuming the dielectric constant of Jena glass to be 6.5, that of "Pyrex" glass must be about 4.3.

A comparison was also made as to the influence of the character of the conducting

medium. Beaker condensers were set up using mercury, concentrated salt solution and distilled water (iron still), respectively. The capacities of the latter two were equal within the limits of error of measurements, while the capacity when using mercury was 10 per cent. higher than when using the salt solution. The slight superiority of mercury at low constant potential seems to be very greatly enhanced at the high and discontinuous potentials employed to produce the spark, where, judging by the fatness of the spark, the capacity of the condenser with mercury is three or four times as great as that of the condenser with salt solution.

This wet condenser has given perfect satisfaction under severe use for many months. Its cost is approximately the same as the glass plate condenser and considerably less than similar condensers covered with tinfoil.

E. KARRER,

H. S. NEWCOMER

THE PHYSICAL LABORATORY OF THE

UNITED GAS IMPROVEMENT COMPANY, THE LABORATORY OF THE HENRY PHIPPS INSTITUTE OF THE UNIVERSITY OF PENNSYLVANIA

PHILADELPHIA, PA.

BOSTON MEETING OF THE AMERICAN CHEMICAL SOCIETY. VI

DIVISION OF INDUSTRIAL CHEMISTS AND CHEMICAL

ENGINEERS

H. E. Howe, Chairman.

S. H. Salisbury, Jr., Secretary. Conference on "The Industrial Chemist in War Time"

The cracking of solvent naphtha in the presence of Blau gas: GUSTAV EGLOFF. Solvent naphtha derived from the thermal decomposition of coal was passed through a carburetted water gas set in the presence of Blau gas at a temperature of 850° C. to produce toluene. The solvent naphtha used gave a distillation range of 93 per cent. between 130° C. and 165° C. First drop at 128° C. and dry at 183° C. Distillation determined by means of a 100 c.c. Standard Engler flask. The percentage yield of toluene in the recovered oil was nineteen, and upon the basis of solvent naphtha used eleven and one half per cent.