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COMPARISON OF SOUNDING Data.

The only condition under which sounding data taken by the deep-sea sounding machine and the Sonic Depth Finder can be compared is over regions where the angle (8) is equal to (π/2), or in other words where the sea bottom is horizontal. Referring again. to Fig. 1, (D1) may perhaps be supposed to represent the depth as determined by the sounding machine (though it is quite possible that the lead may strike bottom at a point some considerable distance from that vertically beneath the ship), and for practical purposes we have seen that the depth may be taken as (H), which we should expect to be less than (D1). The difference between soundings taken by the two methods may be represented by the difference between (D1) and (H) and this value divided by (H) gives the variation in per cent. between the two methods, or

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The following table gives this percentage variation for various values of (8) and also the actual variation for a depth of 1,000 fathoms.

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Remembering that (B), the slope of the sea bottom, is the complement of (8), it will be seen that the percentage variation between the sounding data given by the sounding machine and the Sonic Depth Finder averages about .15 of a per cent. per degree of slope and that the actual difference in the data amounts to about 1.5 fathoms per degree of slope for every 1,000 fathoms depth.

PRACTICAL RESULTS.

The first practical design of the Sonic Depth-finding apparatus was installed on the U.S.S. Ohio and successfully tested in February, 1922, during a cruise from New York along a course running southeast from the Ambrose Light Ship to the latitude of Cape Henry and thence west into Chesapeake Bay. The greatest depth encountered was about 1,700 fathoms. The following June this apparatus was transferred to the destroyer U.S.S. Stewart just previous to her departure for Manila by way of Gibraltar and the Suez Canal. Throughout the run to Manila soundings were taken at least every twenty minutes and at times as often as every minute. The greatest depth encountered was about 3,200 fathoms. This ship is still based on Manila and during the past two years has collected a large amount of sounding data. Her reports state that almost no troubles have been experienced in connection with the sound installation. The Stewart will probably return this year by way of the Pacific, thereby completing a line of soundings around the earth.

Following the success of the Stewart, the destroyers Hull and Corey were equipped with the depth-sounding apparatus and directly proceeded to make a survey of about 35,000 square miles of the sea floor off the coast of California. This survey, which extended from the 100-fathom curve out to a depth of 2,000 fathoms was completed at the rate of about 1,000 square miles per day. These ships reported that the acoustical sounding apparatus gave no trouble and that it was rugged and able to withstand the adverse conditions often met with on sea-going vessels.

Since that time several other ships of the Navy have been equipped as has also the Coast and Geodetic Survey Ship Guide. These ships are taking soundings during every cruise with the result that the Hydrographic Office is receiving an enormous amount of reliable deep-sea sounding data which has already served to clear up several doubtful regions on the navigational charts and which is rapidly leading to an accurate charting of the depth along the main traffic routes. These data have disclosed discrepancies of hundreds and even thousands of fathoms between the actual depth and the old charted values and the discovery of submarine mountain peaks or ridges rising several thousand feet above the sea floor is not un

usual. These landmarks will doubtless prove to be valuable for determining the location and progress of merchant ships that are provided with apparatus for taking deep-sea soundings.

The scientific value of the data that can now be collected with the sonic depth-finding apparatus can scarcely be overestimated. Such data will doubtless furnish valuable information concerning the movements of the earth's crust for the reason that the contour of the sea floor, which has been protected from the processes of erosion, is the direct result of such movements and also for the reason that the most unstable regions of the earth's surface, where the movements are so great and so violent as to affect areas far beyond their origin, form a part of the sea bottom. It may be expected that a careful study of the form and movement of the sea floor brought about by the earth-warping forces will lead to a better understanding of these forces.

CONCLUSION.

Research work dealing with submarine acoustics which the U. S. Navy has carried out during the past five years has led to the development of methods and apparatus capable of aiding and safeguarding navigation by enabling the navigator to locate sound beacons to a range of several miles and to readily determine the depth of water beneath his ship at all times. By means of this same apparatus it is possible now for the first time in history to accurately survey the ocean floor and a large amount of data pertaining to such a survey is being collected by the various ships of our Navy. While it is impossible at this time to estimate the importance of such a work it seems certain that any undertaking that adds to our meager knowledge of the great ocean areas must eventually prove to be a benefit to humanity.

U. S. NAVAL RESEARCH STATION,
BELLEVUE, D. C.

SEX IN THE RIGHT AND LEFT SIDES OF THE

BIRD'S BODY.

BY OSCAR RIDDLE.

(Read April 26, 1924.)

Much recent work indicates that sex in higher animals, though normally determined on a very definite and well-known genetic plan, is a very plastic, modifiable and even a reversible character. Other quite recent studies make it nearly certain that many of the "hermaphrodite " vertebrate animals described during the past few decades were not founded upon a genetic basis-as has been supposed by most biologists-but were really stages of sex-reversal which are to be described in physiological terms. Still other data on sexuality are coming to hand for which also it is fairly clear that physiology rather than genetics must supply the explanation. It is, apparently, a case of this kind with which these remarks are concerned.

If other data did not already indicate the plasticity of sex it would perhaps appear incredible that the two points at which the germ glands arise and develop on the right and left sides of the bird's body are points unequally favorable for the development of male and female sex glands. Even to some of those who regard the plastic nature of sex as fully demonstrated the suggestion that this positional relationship has a real sex significance may perhaps at first seem a rather astounding suggestion. It is not assumed that all biologists are ready to agree to the reversible nature of sex; and we may also grant that possibly the conception to which we now invite attention is wholly wrong. It is here our purpose, however, to mention four kinds of facts which seem to suggest the reality of the proposition stated above. Whether this conception is right or entirely wrong it will certainly require attention until several lines of fact now at hand are otherwise adequately explained. It may be said at once that we are not necessarily concerned with the right and left side of the bird's body as a whole, as our title might suggest,

but merely with the points on the right and left sides at which the germ glands arise and develop.

The first kind of evidence to be presented is based on two series of facts: (1) It has long been known that in female birds the right ovary, though it forms in the embryo, begins to atrophy shortly before hatching and no right ovary is normally present in the adult bird. This is apparently true of all species of birds. Lilienfeld, Nagel and Pick have all made short comment on the bearing of this different expression of femaleness on the right and left sides of the bird's body. Apart from any theory it is a fact that ovarian tissue develops to a far greater extent on the left side in all birds. This fact standing alone would appear to have a sexual significance; when considered in connection with the facts next to be mentioned concerning testis size on the two sides of the body such a significance becomes wholly probable. (2) The other half of this situation has been learned chiefly in our own studies. In two earlier reports we have shown in part, and can now establish the fact satisfactorily on a number of species of pigeons, that in most cases (enough to establish a definite rule) the right testis of pigeons is larger than the left.

In connection with the above observation we are learning that disease, confinement of the animals, and hybridity are all agencies which markedly affect the better development of the testis on the right side. They all lessen the proportion of pairs of testes in which the right is the larger (Table I.). Incidentally it may be noted that it is now becoming clear that each of these three factors has a definite effect either upon sex expression (including change in gonad size) or upon the sex ratio; we also think there is good evidence. that they may and sometimes do profoundly modify sex itself. When these modifying factors are applied to data earlier obtained by others (for relatively few species in other orders of birds), and after personally securing some fragmentary new data for some of these forms, we obtain at least some evidence for a wider application of this observation to other birds than pigeons.

The insufficient data as published, however, are in opposition to the situation found in pigeons. Etzold, Gadow and others report larger left testes in birds in general. It now seems probable that failure to consider effects of confinement, disease and hybridity,

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