April 29, 1909] 



NA TURE 



259 



they are not, emitted by the surface. They find the 

 agreement between theory and experiment altogether un- 

 satisfactory, and conclude that the present theory is not 

 a correct representation of the phenomena of emission of 

 electrons from glowing bodies. 



The March number of Terrestrial Magnetism and Atmo- 

 spheric Electricity contains an abstract by the author, 

 Dr. L. A. Bauer, of the report recently issued by the 

 United States Coast and Geodetic Survey, dealing with 

 the results of the magnetic survey work in the country 

 up to 1906. This report is the most complete summary 

 published up to the present, and supersedes previous re- 

 ports. ' The stations used in the survey are on the average 

 thirty-one miles apart, and the charts cover a considerable 

 area of the surrounding ocean. All values relate to 1905 

 January i, and are corrected for diurnal variation. The 

 secular changes in the United States appear to be much 

 more complicated than has been supposed hitherto, and if 

 cyclic must have subperiods as well as a principal period. 

 Dr. Bauer is already examining the data with the view 

 of determining what part of the magnetic field is refer- 

 able to a potential, and hopes to base other investigations 

 on the material the report supplies. 



The Journal of Physical Chemistry has during recent 

 months been occupied largely by a series of papers by 

 Prof. Bancroft on the electrochemistry of light. In the 

 fourth and fifth papers of the series the " problem of 

 solarisation " is discussed at length, the two papers cover- 

 ing ninety pages of the January and seventy pages of the 

 March issue. Bulky quotations are given from the 

 original literature, and the monograph therefore does for 

 one branch of modern scientific work the same service 

 that Ostwald has performed by reprinting various classics 

 of exact research. The February number will be read 

 with interest, as it contains Kahlenberg's reply to the 

 criticisms of Cohen and Commelin of his work on the 

 osmotic pressure of solutions in pyridine with a rubber 

 membrane. It will be remembered that Kahlenberg 

 obtained pressures for inferior to those deduced by means 

 of the gas-equation ; Cohen and Commelin, with an 

 improved apparatus, also failed to reach the calculated 

 pressures, but attributed their failure to experimental 

 imperfections. In the present communication the validitv 

 of the original experiments is maintained, but no new 

 evidence of importance is brought forward. 



One of the principal machines to which the require- 

 ments of a modern boiler-house have given birth is the 

 automatic recorder of carbon dioxide. Such recorders are 

 devised to take samples of the flue gases at intervals of, 

 say, two or four minutes, analyse them for the percentages 

 of CO,, and record the results on a chart driven by a 

 clock. .A continuous record is thus obtained throughout 

 the whole period at which the boilers are at work, and 

 is of value in showing whether proper conditions for main- 

 taining complete combustion have been preserved, .^s llie 

 record is visible at all times, stokers rapidly learn to pre- 

 serve economical conditions. .Some tests on the Simmance- 

 Abadv combustion recorder have been made recently by 

 Mr. Rosenhain at the National Physical Laboratory, and 

 are commented on in Engineering for April 16. Samples 

 giving 4-99 per cent, of CO, by the Sodeau hand analysis 

 apparatus were recorded by the automatic instrument as 

 4-91 piT cent., the draught being 0-75 inch of water. 

 This riNuIt corresponds to an avoidable loss in fuel of 

 32 per cent. Another sample, showing 9^09 per cent, by 

 hand test, was automatically recorded as 8-98 per cent., 

 the avoidable loss of fuel in this case being 10 per cent. 



NO. 2061, VOL. 80] 



Another sample, showing 1588 per cent, by hand test, was 

 recorded as 15-39 ?<=>■ cent. ; this percentage represents the 

 highest possible under economical working with bituminous 

 coal. Taking the mean of all the tests, the recorder was 

 less than half of i per cent. low. As the charts are 

 graduated to read to i per cent, only under ordinary con- 

 ditions, the results of the trials must be regarded as 

 extremely satisfactory for this recorder. 



A PAPER on problems connected with the construction of 

 the New York Times building was read by Mr. C. T. 

 Purdy before the Institution of Civil Engineers on 

 April 20. The Underground Railway passes through the 

 basement of the building, and the paper describes the 

 special features of the steel construction due to the exist- 

 ence and operation of the railway. The height of the 

 building from the pavement to the twenty-third storey is 

 329 feet, and above this is an observatory and lantern, the 

 roof of 'which is 30 feet higher ; the basement storeys ex- 

 tend 48 feet below the level of the sidewalk. The total 

 dead weight of the building is 33,611,000 lb. (15,000 tons). 

 The problem of vibration arising out of the Underground 

 Railway needed special treatment. In addition to making 

 the structure of the subway independent of the building, it 

 was arranged to found the supporting columns of the 

 former on cushions of sand, and thus still further to 

 insulate the building. The results at first were quite 

 satisfactory, and no vibration was felt from passing trams; 

 but later distinct vibration was detected, and at last this 

 became very pronounced. Seismograph observations were 

 taken and a thorough examination of the two structures 

 was made. The trouble disappeared when the railway 

 company re-laid the tracks through tlie building, all per- 

 ceptible' vibration then ceasing. The author considers, 

 nevertheless, that the insulation of the two structures and 

 the provision of the sand-cushions for the subway columns 

 have a material effect in producing this result. Under 

 many conditions such insulation of structural members 

 would be the most effective and economical method of 

 preventing vibration. It is stated that it was certainly 

 efficient in the new building, which has four railway tracks 

 through it, and often three or four trains in the building 

 at the same time, some stopping and others passing 

 through at high speeds. 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in Mav :— 

 May I. I2h. Jupiter stationary. 



5. gh. 43m. Satellite III. occulted by Jupiter, reappear- 

 ance I3h. :2m. 

 5. Red spot visible on Jupiter's disc between bh. 



and gh. 

 7. Red spot visible on Jupiter between loh. and ilh. 

 13 3h. Mars at quadrature to the Svin. 

 16. 3h. 33m. Satellite III. transits Jupiter's disc, egress 



19. lib. 34ni. Venus in conjunction with the Moon 



(Venus 1° 6' N.). . r. r u c 



20. 4h. Mercury at greatest elongation L. ot the :3un 



(22° 22'). ^ . 



23. 7h. 28m. Satellite III. transus Jupiter, egress 



loh. 57m. ■ , , Ar 



26. Ilh. 5m. Jupiter in conjunction with the Woon 



(Iupiter4° 13'S.). 

 26. 23h. Jupiter at quadrature to the Sun. 

 30. Ilh. 27m. Satellite III. transits Jupiter, egress 

 I4h. 56m. 

 The Meteoric Shower of Halley's Comet.— Mr. 

 W. K. Denning writes : — 



•' The stream of meteors radiating from near t) Aquarii 

 in the mornings between May i and b should be looked 



