202 



NATURE 



[October 22, 1914 



present. In all these cases the stimulus or sugf- 

 gcstion may be made by the official, but it is 

 evident that the hope of developments along- these 

 lines lies in the enterprise of the manufacturer. 

 Preserving, curing, and tinning are operations 

 demanding machinery and commercial aptitude 

 and resources. Perhaps the genius of British 

 commerce lies rather more in business organisa- 

 tion, distribution, and the like, than in actual 

 production — at least, such must have been its 

 tendency in times of peace and prosperity. But 

 we have seen that in such a time of national 

 stress as that through which we are passing 

 purely personal commercial interests have been 

 subordinated — the price of fish, for instance, 

 would doubtless have been higher than it is now 

 but for a self-denying ordinance on the part of 

 the distributing trade. National emergency may 

 well be the stimulus to increased development of 

 the sea-fisheries if only the public will back up 

 efforts on the lines we have indicated. J. J. 



THE TOTAL SOLAR ECLIPSE EXPEDITION 

 TO HERNOSAND, SWEDEN. 



IT had originally been arranged by the Joint 

 Permanent Eclipse Committee of the Royal 

 and Royal Astronomical Societies that a party 

 consisting of Prof. Fowler, Mr. Curtis, and 

 myself, with Major Hills and Father O'Connor 

 as volunteer observers, should proceed to Kiev in 

 Russia to observe the total solar eclipse of August 

 21. However, difficulties having arisen with 

 the Russian Government, with regard to the 

 admission of Father O'Connor and myself into 

 the empire, on account of the categorical law 

 excluding Jesuits, it was found necessary to 

 divide the expedition, and ultimately a party con- 

 sisting of Father O'Connor, Mr. G. J. Gibbs, 

 Mr. E. T. Whitelow, and myself, proceeded to 

 Hernosand in Sweden. Leaving Hull on July 28, 

 and Stockholm on August 2, we arrived at our 

 destination on August 3. 



Through the kind offices of Prof. B. Hassel- 

 berg, of Stockholm, the head of the Swedish 

 eclipse committee, and the assistance of Father 

 Wulf, of Valkenburg, who with his assistant. 

 Father Rod^s, was proceeding to Hernosand, 

 we secured an excellent site for our instruments 

 in a field adjoining the Technical School. Not 

 only so, but the rector of the school, Herr Tham, 

 with extreme kindness and courtesy, placed the 

 whole establishment, with well-equipped labora- 

 tories, dark room, mechanical and carpenters' 

 shops, practically at the entire disposal of the 

 astronomers of the two parties. 



Father Wulf erected his apparatus in a large 

 lecture room facing due south, and Father Rod^s 

 had a fine coronagraph mounted equatorially in 

 an adjoining portion of the grounds. Father 

 Wulf made successful observations of the exact 

 duration of totality, and the times of second and 

 third contacts, by means of an Elster and Geitel 

 potassium photo-electric cell. This formed one 

 arm of a Wheatstone bridge and was balanced by 

 •Nin o-j/iT ■\TrtT r\A~\ 



a resistance of several megohms, the resistance 

 of the other two arms being furnished by those 

 of the battery of many cells which supplied the 

 current to the electrometer. The difference of 

 potential, due to the ionisation of the helium and 

 argon contained in the cell, with a corresponding 

 alteration in its resistance, caused by the variation 

 in the intensity of the light falling on the face of 

 the cell, affected a thin wire, i/500-mm. thick, 

 in the special electrometer invented by Father 

 Wulf, which was displaced laterally. These dis- 

 placements were recorded on a suitable drum with 

 ample scale on the photographic film, which was 

 clock-driven. A thin wire attached to a pendulum 

 beating seconds passing in front of a source of 

 artificial light gave the time scale. 



Our own equipment (Fig. i ) consisted of three 

 coronagraphs of 20 ft., 30 in., and 12 in. focal 

 lengths, and a large spectrograph of the Littrow 

 form. The three coronagraphs were mounted in 

 echelon in front of a i6-in. coelostat, being placed 



Fig. I. — I be ecli] se instru rents, HernTj-and. 



in the azimuth of sunrise. The same coelostat also 

 supplied a beam of light to a 3-in. Cooke lens, 

 which projected an image of the sun 4^ in. in 

 diameter on a graduated screen of ground glass, 

 so as to obtain the angles subtended by the cusps 

 at the sun's centre 10 minutes, 5 minutes, and 

 10 seconds before totality. This instrument was 

 mounted above the 20-ft. coronagraph, so that 

 Father O'Connor, operating the coronagraph, 

 was also able to give the signals at the stated 

 times before totality. The 30-in. and 12-in. 

 coronagraphs were under the charge of Mr. 

 Whitelow, who also made exposures before and 

 after totality with a Zeiss single Protar lens of 

 14-in. focus, working at //16. This camera was 

 mounted on a tripod with wedge head cut to the 

 latitude of Hernosand. He obtained photographs 

 of the moon projected on the corona 30 seconds 

 and I minute after totality. The optical parts 

 of the Littrow spectrograph consisted of a single 

 dense glass prism, 7-in. edge and angle 40 , 



