April 12, 1906] 



NA TURE 



569 



for March. The committee had under consideration a Bill 

 before Congress proposing that, from July i, 1908, all the 

 departments of the Government of the United States, in 

 the transaction of business requiring the use of weight 

 and measurement, shall employ and use the weights and 

 measures of the metric system. Dr. Bell gave an ex- 

 haustive account of the anomalies of the British systems 

 of measurement in use in the United States. He pointed 

 out that all civilised countries, with the exception of the 

 United States and Great Britain and her colonies, have 

 adopted the simpler and more scientific decimal system. 

 He reminded the committee that the metric system was 

 legalised in the United States in 1866, and that its adop- 

 tion by a portion of the population had increased the 

 present confusion. By reference to the decimal system of 

 coinage already in use in the States, Dr. Bell provided 

 convincing instances of the simplification possible with it 

 in the conversion of units, and explained that the United 

 States, when it changed from the old system of pounds, 

 shillings, and pence to the present dollars and cents, did 

 not adopt the metric system of weights and measures be- 

 cause the latter, as we know it, did not appear until after 

 the American Coinage Act of 1792. The facts that our 

 whole system of arithmetic is decimal, that no difficulty- 

 whatever is experienced by ordinary workmen in the use 

 of the metric system — provided there is no question of con- 

 verting their measurements — and that the use of the metric 

 system need not mean the use of new tools, were all 

 clearly explained. It is interesting to note, in connection 

 with this Bill before Congress, that the committee on 

 publicity of the Metrological Society, of which Prof. Simon 

 Newcomb is chairman, has circulated a letter urging all 

 persons in favour of the introduction of the metric system 

 to write, and also secure from other friends, as many 

 letters to representatives in Congress as possible, so that 

 they may see that public sentiment is in the direction of 

 the adoption of decimal weights and measures. 



In the Proceedings of the American Academy of Arts 

 and Sciences, xli., 24, for February, Mr. B. O. Pierce 

 describes, with diagrams, experiments on the manner of 

 growth of a current in the coil of a nearly closed electro- 

 magnet, as influenced by the width of the air gap. 



We have received part i. of the Transactions of the 

 English Ceramic Society for the session 1905-6, and notice 

 that, in view of the greatly increased activity of the society, 

 it has become necessary to issue its publications in a serial 

 form, instead of in a single volume at the completion of 

 the session, as was formerly the case. The present number 

 contains five papers read before the society during 

 November and December of last year. 



OUR ASTRONOMICAL COLUMN. 



Comet 1906c. — The following extension of Dr. E. 

 Stromgren's ephemeris for comet 1906c is taken from 

 Circular No. SS of the Kiel Centralstelle :— 



Ephemeris 12/1. Berlin M.T. 



1906 



h. 



April 10 ... 376 ... + 13 40 



14 ... 3 15 40 ... + 16 19 



iS ... 3 23 54 ... +18 45 



22 ... 3 31 52 ... +20 59 



2 ° ... 3 39 38 ••• +23 4 



30 .. 3 47 14 ... +25 o 



log A Bright- 



029I2 ... 0-37 



030S4 ... 0-31 



0-3249 ... 0-27 



0-3405 ... 0-23 



O3553 - °'2° 



03693 ... 0-17 



Brightness at time of discovery = 10 = about mag. So. 

 NO. I902, VOL. 73] 



This object is now apparently leaving the constellation 

 Aries for that of Taurus, and will pass through the 

 Pleiades group on April 26-27. 



In reference to the paragraph on comet 1905c on p. 545, 

 where it was stated that that comet, also, would pass near 

 to the Pleiades, the latter name was given in mistake for 

 the Hyades. 



Measurements of Linne during the Total Eclipse of 

 the Moon. — In Circular No. 113 of the Harvard College 

 Observatory, Prof. E. C. Pickering publishes the results of 

 a series of measurements of the bright spot around the 

 lunar crater Linn6, made by Mr. R. II. Frost during the 

 total eclipse of the moon which took place on February 8. 



These results show that the diameter of the spot began 

 to increase as Linne 1 passed into the earth's shadow, and 

 to decrease rapidly on the return of sunlight to that portion 

 of the moon's surface. 



This apparently confirms Prof. W. H. Pickering's theory 

 that the phenomenon is due to the formation and melting 

 of hoar-frost. 



The Temperature of the Sun. — An important paper 

 bearing on the question of the temperature of the sun's 

 surface was communicated to the Paris Academy of Sciences 

 by M. Henri Moissan on March 19. 



In the course of his well known experiments with the 

 electric furnace, M. Moissan recently succeeded in dis- 

 tilling titanium, and from the temperature therein employed 

 he deduces probable limits for the temperature in that part 

 of the sun's body where, as seen from the solar spectrum, 

 titanium is volatilised. 



The temperature of the arc employed has been previously 

 determined as about 3500 C, and, taking into account the 

 uncertainty as to the pressure existing in the solar atmo- 

 sphere, M. Moissan concludes that the probable tempera- 

 ture varies between Prof. Wilson's estimated value of 

 6590 C. and the value obtained by M. Violle, viz. 

 2000° C. to 3000 C, the probability being that the latter 

 value is nearer to the truth (Comptes renins. No. 12). 



The Melbourne Observatory. — The thirty-ninth annual 

 report of the work done at Melbourne Observatory deals 

 with the period April 1, 1904, to March 31, 1905, its chief 

 point being a statement of the progress of the work in 

 connection with the Astrographic Chart. To this end the 

 astronomical work has been almost entirely confined to 

 meridian observations and stellar photography. 



The catalogue series now totals 1 149 satisfactory plates, 

 and is complete, whilst for the second catalogue series 455 

 plates have been obtained. For the chart series, with single 

 exposures of 60m., 565 plates have been passed, thus com- 

 pleting this part of the work. Four hundred and ninety- 

 five plates, with triple exposures of 30m. each, have also 

 been obtained for the chart. 



On March 31, 1905, 317 Sydney and 612 Melbourne 

 plates, containing 177,069 and 206,604 stars respectively, 

 had been measured. 



The measurement of the long series of magnetic curves 

 extending back for thirty-seven years was nearly completed 

 when the report was issued, 37,212 day-curves out of about 

 40,000 having been measured. 



Mounting the 6o-inch Reflector at Harvard. — An 

 interesting description of the method which is being 

 employed in mounting the late Dr. Common's 60-inch re- 

 flector at Harvard College Observatory is given in No. 3, 

 vol. xiv., of Popular Astronomy. 



Instead of being supported on a solid pier, nearly the 

 whole of the weight of the instrument is borne on a 

 cylindrical steel float partly submerged in a tank of water, 

 and so fitted as to be perfectly steady. 



The coude method of mounting has been employed, so 

 that the observer may remain in a comfortably fitted room 

 and make his observations through an eye-piece which 

 retains a constant position and direction. 



Electric motors have been employed to drive the tele- 

 scope, and, by a number of switches conveniently placed in 

 the observing room, the observer is able to maintain full 

 control over all the necessary adjustments. 



