cluding 9 ladies, among whom were Vernon Bailey, J. W. Chickering, F. V. Coville, L. H. Dewey, D. G. Fairchild, B. T. Galloway, J. M. Holzinger, L. O. Howard, F. H. Knowlton, C. L. Marlatt, J. N. Rose, W. H. Seaman, E. F. Smith, Theobald Smith, Effie A. Southworth, C. W. Stiles, W. F. Swingle, W. A. Taylor, George Vasey, wife and daughter, M. B. Waite, L. F. Ward, and T. A. Williams.

The Botanical Seminar, an informal society without regular officers, was organized early in 1893 by Messrs. Waite and Fairchild, including as charters members Frederick V. Coville, D. G. Fairchild, B. T. Galloway, Theodore Holm, E. F. Smith, and M. B. Waite. This society grew rapidly, meeting at the homes of the members, until a limit of 25 was reached. Then, as the members were mostly interested in plant pathology and physiology, those interested in systematic botany met at the home of C. L. Pollard on November 11, 1898, and formed the Washington Botanical Club, with Dr. E. L. Greene as President and Mr. Pollard as Secretary. These meetings also were held at the members' homes, and the rapid growth in the next three years again brought the society to the point of necessity of restricting its membership, if the meetings were to be continued at private residences. As a result a committee consisting of O. F. Cook, M. B. Waite, and H. J. Webber for the Botanical Seminar and W. R. Maxon, C. L. Pollard, and David White for the Botanical Club were appointed to consider a combination of the two organizations and the securing of adequate quarters for caring for the constantly increasing number of botanists in Washington, with the result that the present Botanical Society of Washington was formed in November, 1901, with A. F. Woods, President; Frederick V. Coville, Vice-president; C. L. Pollard, Recording Secretary; H. J. Webber, Corresponding Secretary; and W. H. Evans, Treasurer. At the end of six months the membership was 57, and has constantly increased since, until at the present time it has reached 175. The society is probably the largest local organization composed entirely of professional botanists.

But little known and yet unique was the National Science Club for Women, although national in character, yet most of

its activities local. It was incorporated April 8, 1893, and issued from Washington Annual Proceedings and a Monthly Journal, but the club apparently went out of existence the latter part of 1899. Numerous botanical papers were published but none relating specifically to local botany.

Feeling the need of a flora of the District with notes and keys that could be used by local amateurs and by the school teachers and children, Mr. C. L. Pollard issued a prospectus with sample pages of such a flora about 1896, and while many of the families were subsequently written up the project was never completed. In continuation of this idea a number of the systematists in the Botanical Society of Washington formed a Seminar for discussing local flora work early in 1906, and as a basis for such work the writer prepared and issued (letterpress copy) in June of that year a compilation of all reported occurrences of plants in the District together with such additions as members of the Seminar could supply. The cards upon which the list was based were distributed by families to various local botanists who were to prepare these families. The work for the next few years was of a desultory character until 1912 when bi-monthly Seminar meetings for work on the local flora were begun at the instigation of Prof. A. S. Hitchcock, and have been held continuously up to the present time. Assignments of families were made to about thirty botanists, but pressure of official duties has resulted in the withdrawal of a few before the completion of the work.

RADIOTELEGRAPHY.-Resonance measurements in radiotelegraphy with the oscillating audion. L. W. AUSTIN, U. S. Naval Radiotelegraphic Laboratory.

For purposes of rough tuning, many workers have doubtless made use of the click heard in the telephones of an oscillating audion circuit when it is brought into resonance with another circuit at proper coupling. As the resonance click has apparently not been mentioned in any of the publications on radiofrequency measurements, it seems probable that it is not generally known that this click offers by far the quickest and simplest

means of making nearly all measurements depending on the determination of resonance. The accuracy is quite equal to that obtainable with sensitive thermoelements, and greatly superior to the accuracy of the detector and telephone method.1

Since the audion circuit itself is not suited to exact calibration, the substitution method is generally used. The following examples illustrate the procedure:

Capacity of an antenna by substitution. The antenna is loaded with inductance so as to give a wave length of five to ten times the fundamental, then the oscillating audion circuit is coupled to the antenna inductance and the audion tuning condenser varied until a click is heard in the telephones. In general, if the coupling is close, the click will be heard at different points with increasing and decreasing condenser capacity. The coupling should then be loosened until both clicks appear at the same condenser setting, or, if this is impossible, the mean setting is taken provided the points are less than a degree apart. Next, leaving the audion condenser on the resonance point, the ground and antenna are disconnected from the antenna inductance and replaced by the calibrated variable substitution condenser. This last is adjusted to resonance with the audion circuit exactly as described above, and the capacity of the condenser is then equal to that of the antenna, subject to a small correction for the natural antenna inductance.

Wave length of a distant station. The receiving antenna and secondary oscillating circuit are first tuned exactly to the distant station, preferably at loose coupling, the audion tuning condenser being adjusted to give the dead point of the beats in the case of continuous wave reception. Next, without changing anything in the antenna or secondary a wave meter is coupled to the secondary and adjusted to resonance by the click method. The reading of the wave meter gives at once the wave length of the sending station.

In a similar way, wave meters can be compared and condensers and inductances calibrated, either by substitution or by making

1 Care must be taken regarding harmonics, in all measurements in which bulbs are used for excitation.

use of the well-known relation existing between the product of inductance and capacity and the wave length.

Besides the simplicity and quickness of this method, it has the advantage that it does away with the necessity for all auxiliary apparatus in the wave meter, and enables measurements of the highest accuracy to be taken on shipboard and in other places where the use of sensitive galvanometers is impossible.

ABSTRACTS

Authors of scientific papers are requested to see that abstracts, preferably prepared and signed by themselves, are forwarded promptly to the editors. The abstracts should conform in length and general style to those appearing in this issue.

GEOLOGY.-Oil shale of the Uinta Basin, northeastern Utah, and results of dry distillation of miscellaneous shale samples. DEAN E. WINCHESTER. U. S. Geol. Survey Bull. 691-B. Pp. 27-55, with maps, sections, and illustrations. 1918.

The geography and geology of the oil shale are described, and the results of many distillations tests are given, which show yields of oil up to 90 gallons per ton of shale. A great many of the samples tested carried from 20 to 30 gallons of oil per ton of shale. There seems to be ample proof that the oil distilled from the oil shale of the Green River formation is largely obtained as a result of the destruction of the partly bituminized vegetable matter contained in the shale. Invariably the shale showing the larger percentage of vegetable débris will yield the most oil and vice versa, but shale beds occurring between beds of rich oil shale may be fully as compact and fine grained and yet yield no oil on distillation. There appears to be no reason why oil migrating into the shales should not penetrate all alike, and the oil might be expected to follow the beds. of least resistance that is the coarser beds of sandstone which are interbedded with the shales. It seems certain that if the oil had migrated into the shale such porous sands would contain at least small quantities of oil that might be obtained by distillation.

It is probable that the oil shales of the Green River formation may have been the source of all the vein hydrocarbons of the Uinta Basin as well as of the asphaltic material that saturates certain sandstones of the region.

R. W. STONE.