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mental ability or in physical well-being. For example, the grades of students who sit at the periphery of a group are appreciably lower than those of students who sit in the center. Again, grades at the rear of a room show greater variation than do those at the front. In general, the grades obtained by a given student are dependent partially upon such factors as his mental ability and physical condition, but partially also upon his position with reference to the rest of the group to which he belongs. The disadvantages arising from an unfavorable position in the group can not be wholly attributed to the size of the lecture-rooms, or to idiosyncrasies of the speaker. It is overcome, in part, during the course of the semester, and it may also be offset by the addition of frequent small sectional meetings; it is increased by such factors as intervening aisles and by unoccupied seats. The disadvantage has been found incidentally to rest upon variations in certain perceptual and attentional factors and upon differences in the type of self-instruction under which the individual works; but essentially to rest upon the varying degrees of social integration which are always present among the members of an assembled group.

Speech and brain patterns: L. W. COLE. Association experiments with nonsense syllables indicate that verbal recalls are due to the presence of brain patterns in which each syllable is under the influence of one branch of the pattern. The interweaving of these patterns accounts for the continued suggestion by similarity of one idea by another, or, in other words, it gives a neural basis for association by similarity. It also gives a reason for verbal lapses of memory in which there is recall of part of one word with part of another when the word sought for is partially forgotten. The theory is merely an extension of Sherrington's conception of reflex patterns and it would replace with a definite meaning such vague terms as "mode" of impression, retention and recall, which are used by many writers for the lack of a more definite term. Finally the experiments with nonsense syllables show that rhythm is the most persistent and permanent element of a verbal impression.

A learning curve starting at approximately zero: E. K. STRONG, JR. A boy of 5 years has been given two minutes drill on addition combinations a day for 150 days. At the start he knew nothing of additions except that one and one made two and that one and two made three and that he could

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count orally to twenty-five. The learning curve obtained in this case does not follow the usual course but runs nearly parallel to the base line for many days and then rises with a positive acceleration. At the end of 158 days it had not suggested a change from positive to negative acceleration.

Methods of error elimination in a mental maze: T. PETERSON. The mental maze method attempts to study maze learning devoid of all the disturbing spatial factors characterizing the usual mazes. The experimenter has before him a picture of a circular maze, with the various parts lettered in a random order. Sitting behind a screen, he calls out to the subject pairs of letters representing bifurcations in the maze and the subject chooses without seeing the maze. Whether the correct letter is called first or last is a matter that is determined by chance. The subject is instructed to get to the goal with as few errors as possible, and is told the number of errors each time on reaching the goal, but he must find out for himself where the errors are. Subject is also timed. Results show backward elimination of errors of entrance to blinds, and relatively early elimination of return "runs," thus substantiating results obtained by the author on rats in different forms of mazes. The tendency to return to the starting place in the maze at first greatly exceeds that expected on the law of probability, but this tendency rapidly yields to that of keeping the forward direction. "Coefficients of learning" for the runs past the several blinds are worked out statistically, each coefficient representing the ratio of probable runs past to probable runs into the blind. These coefficients are found to increase toward the goal end of the maze, thus accounting for the backward elimination of errors; and the advantage for learning at the goal-end of the maze over the entranceend is shown to be greater than in mazes with many than in those with few blinds. Moreover, this advantage is greater in the first trial than in subsequent trials by any subject; it decreases with successive trials, thus favoring more rapid learning in early trials. Statistical calculations as to the number of errors in each part of the maze on the expectations of chance laws, lead to the conclusion that, independently of the backward elimination tendency, learning progresses more rapidly, in proportion to exercise, in the first and in the last part of the maze than between the extremes.

The development and functioning of a concept in problem-solving: J. C. PETERSON. An objective study is made of the reactions of adults to a num

ber of series of closely related novel problems. In the solution of successive problems of a series the essential common elements are gradually abstracted and associated with an appropriate symbol of some sort. There thus develops a general concept which functions increasingly in succeeding problems in directing observation and controlling re-formulation of hypotheses, until finally new problems are solved at sight or a general formula is given for all problems of the series. In the solution of successive series of problems further functioning and development of the concept occur, enabling the subject finally to generalize correctly in advance for new series of problems of the same type. The order of abstraction of essential situation-elements was found to follow closely the order of frequency of the subject's reactions to them. This is also the order of their temporal nearness to the goal or end of the trial. The recombination of essential elements in connection with appropriate symbols, and their association with effective responses, follow the same order though somewhat less closely. There was usually a high degree of transfer of the effects of learning from problem to problem and from series to series of problems. The median percentage of transfer from the first to the second series was almost invariably surpassed by subjects who required more than the median number of trials for the mastery of the first series. This high degree of transfer in the work of slow learners appears to have arisen from the greater strength of mechanical associations rather than from a deeper insight into the causal relations involved. However, the basic concept mentioned above appears to have been the principal medium of transfer. Yet it should not be forgotten that this concept functioned through specific associations which had become mechanized to a high degree largely through repetition.

EDWARD K. Strong, Jr.,
Secretary

GENERAL MEETING OF THE AMER

ICAN CHEMICAL SOCIETY

THE 59th meeting of the American Chemical Society was held at St. Louis, Mo., April 12 to Friday, April 16, 1920. The council meeting was held on the 12th, a general meeting on April 13th, both in the morning and in the afternoon, divisional meetings all day Wednesday and Thursday morning, and excursions, Thursday afternoon and Friday. Full details of the meeting and program will

be found in the May issue of the Journal of Industrial and Engineering Chemistry. The registration was slightly over one thousand, eight hundred and twenty-five enjoying the smoker.

General public addresses were given by Paul W. Brown, editor and publisher of "America at Work," on "The Physical Basis for the Economical Development of the Mississippi Valley," by Chas. H. Herty on "Victory and its Responsibilities." The chief public address was given in the assembly room at the Central High School on Chemical Warfare" by Col. Amos A. Fries, director of the Chemical Warfare Service.

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The following Divisions and Sections met : Agricultural and Food, Biological, Industrial Chemists and Chemical Engineers, Organic, Pharmaceutical, Physical and Inorganic, rubber, and water, Sewage and Sanitation Divisions and the Dye, Leather, and Sugar Sec tions. Further details of their meetings will be found in the May issue of the Journal of Industrial and Engineering Chemistry.

The banquet, held on Thursday evening, April 15, filled the large banquet hall of the Hotel Statler.

A general business meeting was held on Tuesday morning, at which resolutions published in the Council Proceedings, this issue, on the death of Professor Alfred Werner were read by Dr. Chas. H. Herty. Also, Ernest Solvay was unanimously elected an honorary member of the American Chemical Society. CHAS. L. PARSONS, Secretary

SCIENCE

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SCIENCE

FRIDAY, MAY 7, 1920

CON PENTS

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MULTIPLEX TELEPHONY AND TELEG-
RAPHY OVER OPEN-CIRCUIT BARE
WIRES LAID IN THE EARTH
OR SEA1

INTRODUCTION

THE "key problem" in the procurement of essential Signal Corps supplies in the United States during the World War, curiously enough turned out to be the production of the necessary braiding machines for finishing insulated wire. The bare wire itself could be obtained, the rubber insulation could be obtained, even the cotton thread with which the braiding was made could be obtained, but the necessary machinery for braiding the thread, which finally led us into the intricacies of the procurement of steel, was never anything like adequate for the enormous demands required in the field.

The braiding capacity of the entire United States, as of September 1, 1918, was about 8,000 miles of twisted pair insulated wire per month, while the requirements for the American forces alone at that date were about 40,000 miles a month. On October 1, 1918, the Allied Council reached the decision that beginning March 1, 1919, it would be necessary for the United States to furnish all of this type of wire used by the Allied armies in the field, and the estimated minimum requirements for this purpose were equivalent to four times around the earth a month. To supply this amount of insulated wire would have required cargo space for overseas

1 Abstract of paper presented to the National Academy of Sciences at the session held at the National Museum, April 27, 1920.

shipment in the amount of 14,000 ship tons a month, but had it been possible to use single conductor bare wire in place of the twisted pair insulated wire, the space required would have been reduced to 2,500 ship tons a month, thus releasing the balance for transportation of food, and other vitally necessary supplies.

It is therefore of paramount importance to diagnose, as far as possible, the technical problems of equipment in the light of past experience and of the present trend of development.

The above facts show the necessity of developing, if possible, new methods by which a reduction may be effected in the enormous quantities of expensive and bulky insulated wire, which was so difficult to procure, and which must now be buried in the earth to a depth of 8 or 10 feet throughout the advance sectors of the front line of a modern army.

THREE MEDIA FOR ELECTRIC WAVE
PROPAGATION

The following reasoning led to the carrying out of the experiments to be described:

1. Since we can already communicate by radio means between one submarine and another submarine, both completely submerged, it was considered that connecting two such stations by a submerged copper wire could have no other effect than to facilitate the propagation of the electric waves between the stations.

2. It was considered possible that the behavior of earth or water under the action of high frequency currents might exhibit greatly different properties from those with which we are familiar at direct or low frequency currents.

3. It was realized that whatever high frequency energy losses might occur in the case of bare wires laid in earth or water, yet the over-all efficiency would be

higher than in the case of radio space transmission where the plant efficiency is so very low.

4. It was noted by the writer in September, 1910, and discussed by him in April, 1912,2 1912,2 that the three-electrode audion could be used as a potentially operated device on open circuits. This arrangement was considered suitable for the reception of the signals over bare wires in earth or water.

PRELIMINARY EXPERIMENTS

The first experiment was an extremely simple one as follows: A bare No. 18 phosphor bronze wire, such as is used for the Signal Corps field antenna, was laid across the Washington Channel of the Potomac River from the War College to the opposite shore in Potomac Park. It was paid out from a small boat with sufficient slack to lay on the bottom of the river. A standard Signal Corps radio telephone and telegraph set, SCR 76, was directly connected to each end of the wire, one set serving as a transmitter and the other as a receiver. At the receiving end of the line the bare wire was directly connected to the grid of the receiving set and the usual ground connection left open. A frequency of about 600,000 cycles a second was used and the line tuned at each end by the usual methods. Excellent telegraphy and telephony were obtained. Care was taken to make this preliminary experiment as simple and basic as possible and precaution taken to insure that the wire itself should be bright and clean entirely free from any grease or other insulating material.

2 Journal of The Franklin Institute, April 1, 1912, "Some Experiments in 'Wired Wireless' Telegraphy for Field Lines of Information for Military Purposes,'' by Major George O. Squier, Signal Corps, U. S. Army.

The success of this simple experiment immediately led to more thorough consideration of the entire subject.

One of the questions to be investigated was the general efficiency of the electron tube when used as a potentially operated instrument. The following experiment

was made:

A strip of wire netting was buried in the snow outside the office of the Chief Signal Officer in Washington and a wire attached thereto leading to the second story of the building. The upper end of this wire was connected directly to the grid of an electron tube. The reason for connecting the grid to the upper end of the antenna is of course obvious if we are to use the tube as a potentially operated device. It was necessary for maximum sensitiveness to connect it to the point of maximum potential of the antenna which in the case of a linear oscillator occurs at the open end. By this arrangement, messages were readily received from distant points in the United States.

These two simple experiments, above described, demonstrated the possibility of transmitting electromagnetic waves along bare wires submerged in water and the use of an electron tube as a potentially operated device for the reception of signals. The technical data will be published later.

SUMMARY

For military reasons, if for no other, as stated in the introduction of this paper, the Signal Corps has recently undertaken certain investigations in the phenomena connected with the transmission of high frequency electromagnetic waves over bare wires in earth and in water.

In carrying out these investigations and in attacking the problems from various angles, the research staff of the Signal Corps laboratory at Camp Alfred Vail,

Little Silver, New Jersey, was directed to carry out experiments on bare wires laid on the surface of moist ground and also buried in earth. The staff at the Signal Corps research laboratory at the Bureau of Standards was directed to investigate fundamentally the transmission of electromagnetic waves over bare wires in fresh water. In addition to this, the engineering staff of the Office of the Chief Signal Officer has carried out from time to time certain experiments of a more or less crucial character which have come up for solution in the prosecution of this work at the other laboratories.

Certain data from each of these groups of engineers have been presented above. The phenomena associated with the transmission of high frequency waves over bare wires in earth or water are obscure and complex, and the writer has formulated no definite theory at the present time.

RESULTS OBTAINED

1. Telephone and telegraph communication has been established between Fort Washington, Maryland, and Fort Hunt, Virginia, across the Potomac River, below the city of Washington, over a distance of about three quarters of a mile, by the use of a bare No. 12 phosphor bronze wire laid in the water to connect the stations. The transmitter consisted of an electron tube oscillator which delivered a current of about 270 milliamperes to the line at a frequency of about 600,000 cycles a second. At the receiving end of the line an electron tube and a 6-stage amplifier were used without any ground connection. With this arrangement good tuning was obtained at both ends of the line, and telegraphic and telephonic transmission secured over the bare wires immersed in fresh water.

2. A resonance wave coil has been devel

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