摘要:

It has been recognized for a considerable time that the drifts of long‐enduring meteor‐trains give us our principal direct information about the wind‐currents in the upper atmosphere. Since the directions and velocities of these currents, as well as their altitudes, are of great interest and importance in studies dealing with the physics of the upper strata, it is quite worth while to obtain all the data possible. The actual observation of meteors is, however, a purely astronomical problem, and only through this can the train‐drifts be derived. The result of such study is therefore one of the happy combinations in which the derived data are valuable directly to more sciences t

ISSN:0002-8606    

DOI:10.1029/TR016i001p00032

年代:1935

数据来源: WILEY

摘要:

On the basis of the earlier measurements of less and Kolhoerster, H. Benndorf (Physik. Zs., v. 27, pp. 686–692, 1926, and Wien‐Harms, Handbuch der Exper. Physik, v. 25‐1, p. 279) considered the effect of the cosmic radiation in producing electrical conductivity in the upper atmosphere. In his theory ions were produced at a rate proportional to the product of the cosmic‐ray intensity by the density of the atmosphere and they disappeared by recombination, the coefficient for which was determined by the theory of J. J. Thomson (Phil. Mag., v. 47, pp. 337–378, 1924). Benndorf concluded that a conductivity 1010times that at the Earth's surface could be produced by the cosmic radiation at 100 km. The increase was due to a hundred‐fold increase in the cosmic‐ray intensity, accounting for a tenfold increase in the number of free ions and a 109‐fold increase in

ISSN:0002-8606    

DOI:10.1029/TR016i001p00035

年代:1935

数据来源: WILEY

摘要:

The measurement at the Mt. Wilson Observatory of the ratio of the intensity of sunlight at 0.32μ to that at λ 0.5μ with the thermoelectric ultra‐violet solar radiometer is now in its eleventh year. The original gold and silver films are on the lens‐plate surfaces that were put on in 1924. The same optical system has been used throughout the series and few changes have been made in mechanical details. The same methods of reduction have been used throughout the series. Figure 1 shows graphs of the monthly average and three months running means of the ultra‐violet (λ 0.32μ) to green (λ 0.5μ) ratio for no atmosphere and of the sunspot‐groups observed on Mt. Wilson (dotted lines are monthly averages and full lines are three‐month running means to smooth the curve). The unit is the average for June 1924. The maximum in the smoothed curve of 1.5 was reached in the autumn of 1925 and in the winter of 1926–27. Another high maximum of 1.4 was reached in January and February 1930. The minimum of 0.9 was continuous throughout almost the entire year 1932. The data here refer to 2730 days on Mt. Wilson. Below this curve is the monthly average “ratio zenith to space” which is the atmospheric transmission‐coefficient for λ 0.32μ with reference to that for λ 0.5μ and above is the monthly average and three months running means of the daily number of sunspot‐groups as observed at Mt. Wilson. Whether there is any evidence of a connection between the ultra‐violet and sunspot‐curves will probably depend on the events of the next cycle. Possibly the major variations in the ultraviolet curve are due in part, at least, to atmospheric ozone which

ISSN:0002-8606    

DOI:10.1029/TR016i001p00037

年代:1935

数据来源: WILEY

摘要:

Fairly complete accounts of the data relating to the auroral spectrum and the state of the upper atmosphere obtained by the writer and his collaborators up to 1933 have been published in a number of papers in the Norwegian series of Geophysical Publications [see references 1, 2, and 3 at end of paper]. During the last few years the writer, in collaboration with L. Harang and E. Tonsberg at the Auroral Observatory, Tromso, has devoted much attention to the following problems:(a) To find means for increasing the accuracy of our wave‐length determinations especially in the region of long waves(b) To make clear the intensity‐variations within the auroral spectrum with respect to varying altitude, type, and color(c) Comparison of the auroral spectrum with that of the night sky(d) The determination of the temperature of the auroral region by means of the nitrogen‐bands appearing in the auroral sp

ISSN:0002-8606    

DOI:10.1029/TR016i001p00038

年代:1935

数据来源: WILEY

摘要:

Cooperating with the American Section of the International Scientific Radio Union, Science Service collects daily data on terrestrial magnetism, the solar constant, sunspots, and other phenomena, in order that they may be distributed by radio and other means to those interested.The United States Navy by giving radio transmission to the daily cosmic‐data message, the United States Army by transmitting by radio to Washington data from outlying points, the United States Coast and Geodetic Survey by furnishing magnetic data, the Mount Wilson Observatory of the Carnegie Institution of Washington by furnishing sunspot‐data, the Astrophysical Observatory of the Smithsonian Institution by furnishing solar‐constant values, the National Bureau of Standards by furnishing Kennelly‐Heaviside layer heights, participate actively and fundamentally in the

ISSN:0002-8606    

DOI:10.1029/TR016i001p00041

年代:1935

数据来源: WILEY

摘要:

Many important lines of investigation involve the accurate measurement of time and the overall precision of the work may in fact rest upon the precision with which measurement of time can he carried out. Examples are to be found in the determination of longitude, in the measurement of the rate of propagation of seismic disturbances, and in isostatic problems involving a precise determination of the acceleration of gravity at various paints over the Earth's surface. To these examples may be added the many uses of time by the physicist, which broadly speaking center around the measurement of frequencies, velocities, and accelerations.

ISSN:0002-8606    

DOI:10.1029/TR016i001p00056

年代:1935

数据来源: WILEY

摘要:

A number of people are still alive who remember when every railroad had its own meridian, and by that time operated its trains. The great trunk‐lines had to change here and there to adapt their time to local time. These train‐times seldom if ever agreed with the local time. For instance, in the Pennsylvania Station at Pittsburgh, there were three different times, one for Philadelphia, one for some point further west, and a third, the local Pittsburgh time. The traveler was constantly in danger of missing his train owing to the doubt and confus

ISSN:0002-8606    

DOI:10.1029/TR016i001p00058

年代:1935

数据来源: WILEY

摘要:

The absolute determination of gravity at the National Bureau of Standards has been practically completed, only a few weeks' work yet remaining. The value found, with all the experimental corrections made that are at present possible, is 980.087, with an average departure from the mean of 0.011. The least‐square probable error would be less than this, about ±0.003, but on account of the considerable spread of the single results this is not a reliable criteri

ISSN:0002-8606    

DOI:10.1029/TR016i001p00060

年代:1935

数据来源: WILEY

摘要:

I have appeared before the Section of Geodesy of the American Geophysical Union a number of times as a speaker on geodetic subjects. Today I shall cover a wider field, the field of mapping. Mapping is a fact‐finding process. Without the facts furnished by maps, geophysicists, geodesists, geologists, and others have difficulty in planning and executing their operations.Need for maps—This country is very poorly mapped. While 45 per cent of its area is covered by topographic maps, only about one‐half of those maps are adequate for modern use. This means that about 75 per cent of our three million square miles have no topographic maps or have maps that are not serviceable. This is a situation that needs corre

ISSN:0002-8606    

DOI:10.1029/TR016i001p00061

年代:1935

数据来源: WILEY

摘要:

The closure of a triangulation‐loop seldom fails to stimulate interest among those engaged on geodetic work. Checks on the accuracy of the field‐work, through the use of side‐and‐angle equations, the inclusion of Laplace joints, and the measurement of base‐lines, do much to indicate the general accuracy of the work; but it must be admitted that the crucial test of the observer's care and skill is ultimately made by means of the loop‐closures of the triangulation‐arcs.The completion, in 1934, of the Georgian Bay section of Ontario triangulation resulted in the closure of a loop having an axial length of about 800 miles. The loop consists of an arc or triangulation extending eastward from the north end of Georgian Bay, through the Sudbury mining district and along the Ottawa River as far as Ottawa. From Ottawa, it is composed of part of the Southeastern and Southwestern Ontario nets, extending southerly to the St. Lawrence, thence westerly along Lake Ontario and Lake Erie, thence northerly as far as Georgian Bay. The area covered by Georgian Bay and some of the adjacent territory constitutes the section of triangulation und

ISSN:0002-8606    

DOI:10.1029/TR016i001p00063

年代:1935

数据来源: WILEY