Tribune Extra*. 



But the case is very different with those observers, 

 Who employ Delisle'a method. They require to know 

 the absolute moment, because one observer is as far 

 away as possible on the opposite side of the eurtii from 

 the other. They cannot communicate, and, therefore, 

 the only way they can compare their time is by knowing 

 the true time at their station. But in order to know the 

 true time it is necessary that the longitude should be 

 known. Suppose in England a certain event happened 

 at 5 o'clock in the afternoon ; then you will know it in 

 New-York as earlier by five hours. It would certainly be 

 difficult to be accurate within a second or two. Now, in 

 order to apply Delisle's method the two observers 

 must know the true time of their stations within 

 a second or two. and while this obstacle 

 might be surmounted in such places as 

 Greenwich, Washington, Paris, &c., yet it would be very 

 difficult to do it iu a desolate place or island on the 

 earth's surface; and that is the difficulty of Delisle's 

 method, [It is very well worth noting that during 

 seasons of observations made betsveen Greenwich, Paris, 

 and Washington, tlie Washington observers, by making 

 a comparison between those results, found the true 

 difference of longitude between Greenwich and Paris. 

 American astronomers were the first to give the true 

 difference of longitude between Paris and Greenwich.] 

 You will notice what we have to do In these two methods 

 ore two very different things. Halley's is easy, and the 

 other is difficult. 



Then comes the history of those matters by which the 

 observations of the next two transits have been deter- 

 mined. By an unfortunate mistake in 1857, repeated 

 later in 18C8, the Astronomer Royal of England came to 

 the conclusion that Halley's method could not be applied 

 to the year 1874, and he came also to the conclusion that 

 it could be applied to the transit of 1882. Therefore, 

 observations were to be made by that method in 1882, 

 and expeditious would have been prepared for that pur- 

 pose, when I chanced, in looking over the arguments of 

 the Astronomer Royal, to discover that he had arrived 

 at a conclusion that was erroneous. I found those state- 

 ments must be reversed; tluit it is in the transit of 

 1S82 that the latter method must be applied, while this 

 year Halley's method can be employed with great cer- 

 tainty. I made the statements accordingly. These pic- 

 tures indicate the point on which my reasoning was 

 based. Here is the earth as seen from the suu at the 

 moment the transit begins. Therefore at any place 

 now In view the beginning of the transit must be seen. 

 Here i. a picture Knowing the earth when the end of the 

 transit of 1874 can be seen. Now, you notice the begin- 

 ning occurring here in North Asia, Japan, &c.; the 

 end can also be seen in those regions. So that the be- 

 ginning and end are thus seen. There is nothing to bo 

 dW)6 hut to place observers in tliosfi parts of the earth 

 and they, seeing the beginning and the end, will know 

 the time it takes. Southern stations also exist, as you 

 see. for seeing tfco whole rr.msit. Therefore, there is 

 nothing to prevent northern and southern observers 

 from oaking thtmo observations necessary to Halley'a 

 method. The northern observer will notice Venus at 

 ttio lowest of those lines, while the southern watcher 



Pamphlet Series. 



will see the uppermost or shortest of those lin ee, 

 Everything they want is ready for them, and al 

 hat is necessary is, that another observer should be^ 

 sent to this part of the earth, to this more desoh.to 

 region [pointing it out on the diagram], and then the 

 whole thing can be accomplished. 



In the transit of 1882 there is a different state of 

 things. Here is the surface of the earth at the begin- 

 ning of the transit in 1882. Here is North America. 

 New-York and Washington are there, and the beginning 

 and end of the transit can be seen from that northern 

 region; but there is no southern place where the whole 

 of the transit can be well seen. There is a great change 

 between these former features and those we have now. 

 The transit will only last four hours in 1874. Toe 

 chord of the tr.,nsit is very short. In 1882 you will 

 notice South America is carried' right away the other 

 side of the earth, and the result is there will be a very 

 great change in all the stations. You will notice the only 

 southern station where the beginning and end of the 

 transit is ever seen is in Possession Island, ana another 

 here at Repulse Bay. But although they are in view 

 there, they are so close to the edge of the disk at 

 the beginning of the transit that at that moment the 

 Bun, I found, would only be four degrees above the 

 horizon. It becomes a difficult problem, a very difficult 

 observation, to tell within a second or two when Venus 

 touches the inside of the sun's edge, and that observa- 

 tion cannot be made when the sun is so low down. 



MR. PROCTOR'S EFFORTS TO OBTAIN A HEARING. 



Then you see the condition of the two transits. You 

 may know that America has done more than her share 

 in that matter. There are as many as seven stations to 

 be occupied by North American observers in these 

 northern regions, and then, beside, they are send- 

 ing observers to this southern region. In this 

 controversy, I must admit I spared no ef- 

 forts. At the beginning of last year, when 

 I found the time was drawing near, I used all 

 means to get my views urged as strongly as possible. 

 The whole controversy has been about this point: 

 whether England will change the arrangements orig- 

 inally made to select and search out the place in which, 

 to see the transit from the Southern regions. I spared 

 no efforts writing in daily, weekly, monthly, quarterly 

 papers, for which I was abused right and left to insist 

 upon the true views of the matter. It is objectionable 

 always to insist upon views, unless there is good reason 

 and the time 1 near when a dadsion must bo taken. 

 Feeling that no time was to bo lost, I for the moment 

 neglected that rule, In order to press my arguments; 

 and last Juno, at a meeting at the Greenwich Observa- 

 tory headed by Prof. Adams, ttie greatest of astronom- 

 ical mathematicians, it was proposed that measures 

 should be taken to search over the sub-Antarc- 

 tic regions, and the proposition was unaui- 

 imously carried by all the astronomers present. 

 That has already been done, and I hope good results 

 will be obtained. One other point I noticed in making 

 my examination. By another great mistake of the 

 Astronomer Royal who, It Mumld be remomb Ted, haa 

 other duties to perform at Greenwich, which t;&o up all 



