July 28, 19 10] 



NATURE 



their flisrht after the exposure is completed. For 

 such cases, M. Bull encloses them in a glass tube 

 with a verv light mica door, which is moved by the 

 insect in its flight, and which, making a contact, sets 

 the shutter mechanism in action. 



In order to study the movements represented on the 

 films, which in nature are far too rapid to be followed 

 bv the eve, it is merely necessary to pass them through 

 an ordinary kinematograph, making some fifteen ex- 

 posures a second instead of the 1500 or 2000 a second 

 employed in taking the photograph, and then the 

 movement, 100 or more times as slow, will be seen, 

 and in many cases easily followed. Where a still 

 greater slowing is required, M. Bull arranges to make 

 the film appear stationary for a much larger propor- 

 tion of the whole interval than is usual, and then only 

 two or three views a second are sufficient to give an 

 apparently continuous movement. C. V. Boys. 



THE TOTAL SOLAR ECLIPSE, MAY 9, 1910. 



THE following two communications from Port 

 Davev, dated Mav 7 and 9 respectively, complete 

 the account of Mr. McCIean's expedition to Tasmania. 

 In spite of the trying weather con- 

 ditions, a very complete installation 

 of instruments was successfully 

 erected, but, as previously re- 

 ported, clouds prevented their use 

 during the eclipse. 



The photographs accompanying 

 the report were taken by Mr. 

 H. Winkelmann, and the three 

 here reproduced have been selected 

 to illustrate the setting up of some 

 of the instruments. 



instruments fed by the siderostat were in accurate 

 position, and some trial photographs were taken with 

 the concave grating spectrograph which on develop- 

 ment proved to be good in e\'ery way. 



" Mr. Short, w^ho arrived on May i, has decided 

 to feed his five-foot camera from an' auxiliary mirror 

 from the siderostat, as, with the wind that is likely 

 to occur, it would not be steady on the equatorial 

 mount, and on this mount have been placed his 

 telephoto and Worthington's camera, as the latter 

 could not be run correctly with his clock. 



" Considerable difficulty had been found in driving 

 the siderostat after about 3.15 in the afternoon, and 

 a device had been put up to help the mirror cell arm 

 round after that time. Owing to bad weather, no 

 complete examination had been possible until May 7, 

 when the mirror and cell were removed, and it was 

 found that one of the balance-arm bearings had not 

 sufficient play to allow the rollers to continue in 

 contact with the cell. Filing down was tried, but 

 there was not sufficient material to do this fully, and 

 so the bearing was reversed. This gave considerable 

 improvement, but before the time at which eclipse 

 would occur it was found that the rollers reached 



Port Davey, May 7, 1910. 



"The weather since .\pril 27 

 was execrable until May 4, and 

 was not good until the follow- 

 ing afternoon. Continuous j^ales, 

 heavy rains, and floods made 

 progress absolutely impossible, and 

 no trustworthy tests were made 

 before May 4. The ground be- 

 came a quagmire, and the in- 

 struments were covered with rust, 

 in spite of paraffin and oil. Rain 

 g'ot into the concave grating slide- 

 holder, and the cloth began to peel FigureT'from 

 off. The coelostat mirror was badly 

 discoloured, in spite of coverings of Japara 

 and Willesden canvas. The siderostat mirror was 

 also permanently fogged and slightly spotted, and ' 

 in the morning, on uncovering (when possible), was 

 covered with moisture. In addition to this, the 

 ground shook at every footstep, and everything 

 vibrated. The barricades proved very useful in pro- 

 tecting the instruments from the wind, which was I 

 so strong that during the gusts it was impossible 

 to walk against it. On several davs no coverings 

 could be taken off, and work was at a standstill. 

 The Wainiti, which came in on May i, had to fake 

 refuge in Schooner Cove on the other side of the 1 

 Bathurst Channel until the following day. Our boat, 

 which had to _ go over to pick up Mr. Short, from 

 Sydney, and his instruments, could not get back, and 

 we had to cross behind Mundy Island and land ; 

 mile across country from our camp, leaving the boal 

 in a cove until the next day. 



" On May 4, however, there were a few intervals 

 of sunshine during the "afternoon, and on May 5 the 

 afternoon was fairly bright after a drizzling^ morning, 

 while May 5 was cloudless and with a gentle breeze 

 from the east, and much progress was made. The 

 NO. 2126, VOL. 84] 



-Beginning the erection of the instruments on Hixson Po!nt. 

 left to right— J. Brooks, F. K. McClean, A. Young, S. Dowsett. 



the end of their slot, and greater power was required 

 to (irive them up the slope. Having no tools for 

 continuing this groove, arrangements were made for 

 a weight to be attached upwards to the cell arm, and 

 this_ was found to answer ; but considerable dangers 

 of irregular drive are present in this method. An 

 attempt was made to work the slow motions from 

 the concave grating spectrograph, but, owing to the 

 distance, no good results were obtained, and Mr. 

 Dowsett was therefore placed in charge of the 

 siderostat to follow instructions from the spectro- 

 graph, where the large image on the slit gives a 

 quick idea of any movement either in right ascension 

 or declination. 



" Drills commenced on May 6 both separately and 

 generally. The allocation of' the instruments to the 

 members of the party has been arranged as 

 follows : — 



Siderostat S. G. Dowsett 



Instruments fed by siderostat. 

 Concave grating spectrograph ... F. K. McClean 

 De la Rue coronagraph ... ... A. Wilson 



Short 5-ft. „ J. Short 



