March 4, 1875 J 



NATURE 



2. Object-glasses and mirrors not to be unscrewed 

 from their cases till telescopes are perfectly mounted. 

 P ream t ions to be attended to half an hour before Totality. 



1. If an aperture has been reduced for preliminary 

 experiments, take care that full apertures are restored. 



2. In case any telescopes are used for eye observations, 

 reminder should be given to take off dark glasses before 

 totality. 



3. Wind up all clocks. 



4. Let all strangers withdraw. 



5. Light lamps. 



Arrangement of Photographic Plates. 



As the plates are smaller than was intended, the 

 spectrum must be thrown along the length of the plate, 

 and if possible, in the prismatic cameras, from corner to 

 corner. 



A shelf should be prepared over the developing table 

 with places marked i, 2, 3, &c. The backs used in any 

 one instrument should be labelled in large letters on both 

 sides, and a similar label should distinguish each shelf 

 The plates will then arrange themselves into series, and 

 can be numbered aftenvards. Care must be taken to have 

 lamps in the dark room. 



The Time Teller. 



One person should be detailed at each station to tell 

 the time. 



The chief observer at each station will give the signal 

 for commencement for totality, which being done, the time 

 assistant will call out the number of seconds of calcu- 

 lated duration at the locality. If, for instance, the totality 

 is four minutes, he will say "You have 240 seconds," and go 

 on calling out every ten seconds the number of seconds 

 still left for work. A clever man can do this in a very 

 encouraging way. The time counter should take care 

 not to distract himself by losing sight of the face of the 

 watch or chronometer, and it is to be impressed upon him 

 that much of the success of the observations will depend 

 on his undivided attention, as his statement of time will 

 be an order to the observers to do certain work. 



Rehearsals. 



There must be at least two complete rehearsals of the 

 whole attack on two previous days at the time of the 

 eclipse, and the final written instructions to each observer 

 given by the chief of the party will mainly depend on the 

 experience of these rehearsals, which must be of a very 

 serious character. It must be recollected that the speed 

 and skill in collodionising and developing can only be thus 

 determined. 



The going of the clocks and counterpoising of telescopes 

 in the particular position in which they will be employed 

 near the time oftotality must be examined with the greatest 

 care, and the best regulation of the clock for this position 

 should be adhered to. In these rehearsals all apertures 

 must be reduced. 



The clock weights must also be examined, and increased 

 if necessary to produce an uniform motion of the telescope. 

 Silence. 



Silence must only be broken by the timekeeper. The 

 rehearsals should be utilised for asking any questions 

 touching any part of the duties of each observer during 

 the observations, and each observer should have his 

 programme of work nailed up where it can be easily 

 seen. 



In order to prevent noise and interruptions, none but 

 the observers and trained assistants should be allowed to 

 be within fifty yards of the observatories, for an hour 

 before and an hour after totality. 



Programme of Work. 



The Programme of Work may conveniently be stated 

 in the time called out by the time observers. In which 



353 



case "200 seconds more," and so on, will become an 

 instruction to one of the observers to do a particular piece 

 of work. 



Notes on the Phenomena Observed. 



Anything an observer has to record should be done 

 immediately after totality, or the last observation after 

 totality. 



Trust nothing to memory ; a note made the next day 

 will be comparatively valueless. 



Multiplication of Results. 

 As soon as convenient after the eclipse, before 

 lea\ing the station, at least four copies of every photo- 

 graph must be made, and enlargements, if possible, 

 in duplicate on glass. Paper copies of these duplicates 

 should be transmitted by two different mails to the Royal 

 Society. The various copies to be sent home if possible 

 by dilferent mails and different routes. One copy to be 

 left in India and given in charge of the chief of the 

 Indian expedition. 



Photographs of the Corona. 

 It will be very desirable for the obsen'ers appointed by 

 the Indian Government to depict photographically the 

 corona as a whole, to take some photographs on plates so 

 placed in the long focus camera (rectilinear lens) that the 

 back of the plate is towards the object-glass and the 

 collodion towards the observer, in order to avoid reflection 

 from the second surface of the glass. Special plate 

 holders will have to be made, and the glass selected as 

 perfect as possible and of nearly the same thickness. Of 

 course the back must be carefully cleaned before the plate 

 is exposed. 



Observations to be reduced by the Royal Society. 



It is understood that the observations made by the 

 members of the English Expedition are the property of 

 the Royal Society, by which body they will be reduced. 

 It is hoped that the Indian Government will allow dupli- 

 cates of the observations taken by the Indian parties to 

 be forwarded to the Royal Society to aid in these reduc- 

 tions, and to enable a general account of the whole 

 attempt to be prepared. The English observers detailed 

 to India will co-operate with the Chief of the Indian sta- 

 tion to which they may go, and will assist in carrying 

 out the arrangements in accordance with the foregoing 

 instructions. 



All experiments made for the furtherance of the ob- 

 jects of the expedition will be carefully recorded and 

 will be considered the property of the Royal Society. 



SCHOLARSHIPS AND EXAMINATIONS FOR 

 NATURAL SCIENCE AT CAMBRIDGE, 1875 



'TPHE following is a list of the scholarships and exhi- 

 ■l- bitions for proiiciency in Natural Science to be 

 offered at the several Colleges and for non-collegiate 

 students in Cambridge during the present year : — 



Trinity College. — One or more scholarships of 100/., 

 and one exhibition of 50/. The examination for these 

 will commence on March 30. Further information may 

 be obtained from the Rev. E. Blore, Tutor of Trinity 

 College. 



St. Johnh College. — One of the value of 50/. per annum. 

 The examination (in Chemistry, Physics and Physiology, 

 with Geology, Comparative Anatomy, and Botany) will 

 commence on April 3, and will be open to all per- 

 sons who have not completed a term of residence at the 

 University, as well as to all who have entered and have not 

 completed one term of residence. There is a separate 

 examination in Natural Science at the time of the annual 

 Collrgi: examination at the end of the academical year, in 



