|
Russel Wallace : Alfred Russell Wallace (sic)
"9, St. Mark's Cresent, Regent's Park, London, N.W. "Sir,--As I presume by your offer in "Scientific Opinion" of January 12th, that you can afford to pay £500 to have the question of the actual rotundity of the Earth proved to your satisfaction, I hereby offer to stake that sum on the undertaking to show visibly, and to measure in feet and inches the convexity of a canal or lake. A canal will do if you can find one which is nearly straight for four miles without locks, if not, I propose Bala Lake, in North Wales as a place admirably suited for the experiment. As an intelligent referee I propose the Editor either of "Scientific Opinion," "The Field," or "Land and Water," or any well-known Land Surveyor, or Civil Engineer, or any fellow of the Royal Geographical Society. "I remain Sir, yours very faithfully, "9, St. Mark's Crescent, N.W., January 21st, 1870. "Sir,--I have ascertained that the Editor of the "Field" is willing to act as referee in the matter between us. I have to propose therefore that we each place £500 at once in Coutts' Bank, 95, Strand, with instructions that, up to March 1st next, it is only to be paid to the order of one of us, on a cheque signed by Mr. John Henry Walsh, the Editor of the "Field," who has an account at Coutts'. After that date the money to be at our own disposal, which will be the case if any unforeseen circumstance over which we have no control, prevent the trial being made. [[p. 15]], "By this means the money will be perfectly safe. The reason I ask for its being deposited at once, is, that I must go to some expense and considerable trouble in getting a telescope and other necessary instruments, and in finding a suitable spot, and as the time you have named is short, I must begin at once, and cannot do without the certainty that the trial will come off. "I may state that the Editor of the "Field" is a perfect stranger to me. "I remain, yours very faithfully, "I believe the Bedford River near Downham Market, Norfolk will have to be the place. The "Field" will publish the result of the experiment.--A.R.W." "9, St. Mark's Crescent, N.W., "Dear Sir,--Your wish to have a second referee is quite reasonable, and I accede to it at once, only stipulating that he shall not be a personal acquaintance of your own, and shall be a man in some public position as Editor, Author, Engineer, &c. "Foggy weather would render the experiment impossible. I should therefore wish that if they are prevented by weather, the time named by you may be extended a month. "Yours very faithfully, "9, St. Mark's Crescent, N.W., "Dear Sir,--I should very much regret if you did not come down to Norfolk to see the experiment I propose to make, yourself. I was going to suggest that you should first meet me there, and only in case I should not be able to make the thing sufficiently plain to you, should we call in the referees at all. I firmly believe I can make it plain to you, and that it would interest you very much to see it, and convince you in a way that no report of referees could do. I have now made all my arrangements, and propose to start for Lynn or Downham Market (the nearest way to the Bedford River) on Friday next, if the weather is at all settled. Will you meet me there, or will you come on Monday and we can remain till a fine day occurs, when a few hours will settle the question? This will be much the best plan, because Mr. Walsh, being Editor of a weekly paper, can only leave town on Monday or Tuesday, and if those days should happen to be bad, I shall have to wait for him another week. But if you come, any day will do, and as soon as it is fine we can telegraph for your referee, Mr. Carpenter, if you wish it. "When the snowy weather is over, it may be very fine, and if you will join me I will go any day you like to fix, but not later than early next week (21st or 22nd Feb.) if convenient to you. Hoping you may be able to agree to my proposal, and that you will fix a day to meet me within a fortnight from this date, "I remain, dear Sir, yours very faithfully, "John Hampden, Esq." "9, St. Mark's Crescent, N.W., Feb. 16th, 1870. "Dear Sir,--I do not wish to make the least alteration in the arrangements, and the referees shall of course attend; but I certainly think, as you have written so strongly on this matter, you should be present yourself. "Till the wind changes, I fear there will be fog in the Fens, but if it looks promising I shall go down on Monday, and if it is clear, telegraph to the referees and yourself. "The test I am going to use is very simple and conclusive. I have prepared half a dozen signal posts, each six feet long, and with red and black circles attached to them, so as to be distinctly seen at a long distance. I shall set these up a mile apart on the water's edge, and then look along them with a powerful telescope. If the water line [[p. 16]], is straight and flat, the tops of these poles will of course be straight and flat too; but if the earth and water has a curvature of 4000 miles radius, then the tops of the poles will be equally convex, and they will be seen rising higher and higher to the middle point, and then sinking lower and lower to the furthest one, and the amount of rising and falling will be nearly the feet and inches I have put down on the diagram on the other side. The upper figure shows what must be seen if the earth is round, the lower what must be seen if it is a plane. "Of course the curvature shown is immensely exaggerated, but with a good telescope it will be easily seen if it exists. "Yours very faithfully, "John Hampden, Esq." "9, St. Mark's Crescent, N.W., Feb. 20th, 1870. "Dear Sir,--I will to-morrow pay £500 to Messrs. Coutts', on conditions identical with those of your £500, and I will request them to inform you of the fact. When you receive this information I trust you will accept my assurance that I had no other reason for not doing so earlier than that which I have already stated. "If the weather is milder and clearer, I shall go down to Downham Market on Monday, February 28th, inviting Mr. Carpenter to accompany me if he thinks proper, and then sending for Mr. Walsh on the Tuesday or Wednesday, if the weather is sufficiently favourable. "I have had much difficulty in getting a telescope of sufficient power. I have one that may do (3 inches object glass and 4 feet long), but should prefer one of 4 inches object glass and five feet long; and these are only made for astronomical purposes. I can only find one in London, and that will not be let out on hire or trial, and only sold (without stand) for £42. I believe, however, I can get the loan of one from Brighton if mine turns out insufficient, and if I cannot get one at Lynn. I have had one telescope on trial already, and found it not good enough. "Believe me, yours very faithfully, "John Hampden, Esq." "9, St. Mark's Crescent, N.W., March 9th, 1870. "Dear Sir,--In accordance with your letter of yesterday, I enclose a memorandum authorizing Mr. Walsh to act in the manner you suggest, which, if you see nothing requiring alteration, please sign and send to him, or if otherwise, write one yourself and send it to me, or send a supplementary one if you have anything to add. With regard to your postscript, I believe you will find that any civil engineer will tell you that the 'decline' you speak of was shown in the spirit-level in the view from both ends--because, on a circle, the place you stand on is always on the top, and in the telescope of the level the signals were always below the level line shown by the cross-hair, and no more could be shown if I went again to the middle station. If, however, the umpire thinks this necessary, he will ask me to show it. "I remain, dear Sir, yours very faithfully, "John Hampden, Esq." "9, St. Mark's Crescent, N.W., March 20th, 1870. "Dear Sir,--In yours of yesterday you imply that Mr. Walsh's decision is an improper one, and that I know it; and that the fact proved by the trial at the Bedford River is worthless and inconclusive, and that I know it. Now I think you will, on consideration, see that it is not fair or honourable to impute to me a belief I have never acknowledged, and which I most emphatically deny and protest against. I firmly believe that the result of the trial proved all you ever asked me, or I ever undertook to prove; and that Mr. Walsh's decision is the only one an honest and sensible man could come to. "You should remember that when, in answer to your request, I sent you a sketch of what I was going to show you, and how, you replied--'I am perfectly satisfied with your proposed plan. It cannot fail to be thoroughly convincing one way or the other.' The plan actually adopted for convenience, with your and Mr. Carpenter's full concurrence--(as shown by a sketch drawn by myself in Mr. Carpenter's notebook, at his request, on the Friday evening before the trial, and agreed by him and [[p. 17]] you as perfectly satisfactory, but which sketch he has declined to exhibit since, and has not sent in to Mr. Walsh)--was essentially the same, yet you now say the experiment is worthless and proves nothing! What will the public say if these two letters are published? "Now for the assertions and challenges in your pamphlet you were so good as to send me. Your proposed further tests are some very good, some quite worthless. All those which in any way depend on an apparent slope up or down, as judged of by the unaided eye, are utterly worthless; because, of all things, the eye is least able to judge accurately of a level, and if a line deviated as much as eight feet instead of only eight inches in a mile, I would defy you to tell by the eye alone if it were level, or sloped up or sloped down. "The good tests are those which propose to determine differences of level or position by the use, either of a first-rate spirit-level, or signals which can be brought to range accurately in a line. "First. The test proposed at p. 5, to place a spirit-level at the middle station, and take a sight both ways to Welney Bridge and Old Bedford Bridge (not Welche's Dam as you state) the water at the two ends would certainly be shown to be about five feet below the horizontal straight line touching the water at the middle station. The only difficulty would be in getting the level placed high enough to be above the vapours and unequally heated air close to the ground; but I have no doubt, if it were placed on the elevated towing path, its height above the water would be about five feet less than the height of the points on the two bridges cut by the cross-hair, which determines the true level line. "2nd. As to the continuation of the curve beyond the three miles in each direction. This is
also a good experiment, and I maintain that a signal staff placed one mile further off than either
bridge, would show the water there to be eight or nine feet below that at the middle station, and
at two miles further off, fourteen or fifteen feet, as it should be if the curve continues--not less
than at the Bridge, as it should be if your theory of a series of short curves, thus-- "3rd. The test of the lamp (p. 8) 18 inches above the water on a clear night at one Bridge, being visible by an eye or telescope situated, say three feet above the water at the other Bridge six miles distant. I maintain that it would not be visible; while, at the same time, it would be distinctly visible from the Bridge at an elevation of about fifteen feet. "Now, on each or all of these three points I am ready, after the present wager has been finally settled, to meet you on any fair terms you may propose, the umpire being any well-known civil engineer, surveyor, optician, or scientific man--the questions all being simple matters of fact, which it requires merely good eyesight, some knowledge of instruments and experiment, and a true tongue, to pronounce upon justly. "I remain, dear Sir, yours very faithfully, "John Hampden, Esq." MEMORANDUM OF AGREEMENT. "The undersigned having each deposited the sum of £500 in Messrs. Coutts' Bank, do hereby agree that if Mr. Alfred R. Wallace, on or before the 15th day of March, 1870, proves the convexity and curvature, to and fro, of the surface of any canal, river, or lake, by actual demonstration and measurement, to the satisfaction of Mr. John Henry Walsh, of 346, Strand, London, and Mr. William Carpenter, of 7, Carlton Terrace, Thornford Road, Lewisham Park, London (or, if they differ, to the satisfaction of the umpire they may appoint), the said Alfred R. Wallace is to receive the above mentioned two sums amounting to £1000, by cheques drawn by Mr. John Henry Walsh to his the said Alfred R. Wallace's order; and if the said Alfred R. Wallace fails to show such actual proof of the convexity of any canal, river, or lake, the above mentioned sums are to be paid in like manner to Mr. John Hampden. Provided always that if no decision can be arrived at, owing to the death of either of the parties, the wager is to be annulled; or if, owing to the weather being so bad as to prevent a man being distinctly seen by a good telescope at a distance of four miles, then a further period of one month is to be allowed for the experiment, or longer, as may be agreed upon by the referees. "ALFRED R. WALLACE. "February 8th, 1870."
|
is true.