International Conference Held at Washington Part 7

These two solutions may be discussed; this has been often done, and again quite recently, by one of our ablest geologists, M. de Chancourtois.

Each of these meridians combine the fundamental conditions which geography demands and upon which there has always been an agreement when national meridians are set aside from the discussion. As to the determination of the position of the point which may be adopted, the present excellent astronomical methods will give it with a degree of exactness as great as that which geography requires.

But what is the necessity for a special and costly determination of the longitude of a point which can be fixed arbitrarily, provided this be done within certain limits, as for instance by satisfying the conditions of pa.s.sing through a strait or an island. We may be content with fixing the position of the point adopted in an approximate manner. The position thus obtained would be connected with certain of the great observatories selected for the purpose from their being accurately connected one with another, and the relative positions thus ascertained would supply the definition of the first meridian. As to any material mark on the globe, if one be desired, though it is in no manner necessary, it would be established in conformity with this definition, and its position should be changed until it exactly complied with it.

As to the question of the changes to be introduced in existing maps and charts which, by our proposition, would be imposed upon everybody, they could be very much reduced, especially if it were agreed--which would be sufficient at first--to draw upon existing charts only a subsidiary additional scale of graduation which would permit immediate use of the international meridian. Later, and as new charts were engraved, a more complete scale of graduation would be given; but I think that it would always be desirable to preserve in the manner now done in many atlases both systems of reckoning longitude--the national and international. If it be necessary at the present time to facilitate the external relations of all nations, it is also well to preserve among them all manifestations of personal life, and to respect the symbols which represent their traditions and past history.

Gentlemen, I do not propose to dwell upon the details of the establishment of such a meridian. We have only to advocate before you the principle of its acceptance.

If this principle be admitted by the Congress, we are instructed to say that you will find in it a ground for agreement with France.

Without doubt, on account of our long and glorious past, of our great publications, of our important hydrographic works, a change of meridian would cause us heavy sacrifices. Nevertheless, if we are approached with offers of self-sacrifice, and thus receive proofs of a sincere desire for the general good, France has given sufficient proofs of her love of progress to make her co-operation certain.

But we shall have to regret that we are not able to join a combination which to protect the interests of one portion of the contracting parties would sacrifice the more weighty scientific character of the meridian to be adopted, a character which in our eyes is indispensable to justify its imposition upon all, and to a.s.sure it permanent success.

Prof. J. C. ADAMS, Delegate of Great Britain, stated that if he were allowed to offer a few observations upon the eloquent address made by his colleague, the representative of France, Mr. JANSSEN, he would remark that, so far as he could follow that discourse, it seemed to him to turn almost entirely on sentimental considerations; that it appeared to him that the Delegate of France had overlooked one great point which was correctly laid down by the President in his opening address, viz., that one of the main objects to be kept in view in the deliberations of this Conference would be, how best to secure the aggregate convenience of the world at large--how we should choose a prime meridian which would cause the least inconvenience by the change that would take place. Of course, any change would necessarily be accompanied by a certain amount of inconvenience, but our object, as he understood it, was to take care that that inconvenience should be as small in its aggregate amount as possible.

He stated that if that were taken as the ground of consideration by this Conference, it appeared to him that the question was narrowed to one of fact rather than to be one of sentiment, which latter would admit of no solution whatever; for it was quite clear that if all the Delegates here present were guided by merely sentimental considerations, or by considerations of _amour propre_, the Conference would never arrive at any conclusion, because each nation would put its own interests on a level with those of every other.

He added that if the Conference should be able to agree in the opinion that the adoption of one meridian (for his part he did not undertake to say what meridian) would be accompanied by a greater amount of convenience in the aggregate than the adoption of any other, he thought that this should be the predominant consideration in guiding the decision of this Conference, on the question referred to them, and it appeared to him that this is a consideration which the Delegate of France has not put before this Conference, at least not in a prominent way. It is clear that the inconvenience caused to any one nation by the adoption of a new neutral meridian would not be lessened by the fact that all other nations would suffer the same inconvenience.

With respect to the question of a neutral meridian, Professor ADAMS wished to call the attention of the Congress to the fact that the Delegates here present are not a collection of representatives of belligerents; that they are all neutral as men should be in a matter purely scientific, or in any other matter which affects the convenience of the world at large, and that this Conference is not met here at the end of a war to see how territory should be divided, but in a friendly way, representing friendly nations.

He stated that he hoped the Delegates would be guided in their decision by the main consideration, which was, What will tend to the greatest practical convenience of the world? That he need not address a word to the other part of the argument which he thought at first of commenting upon a little, for the Delegate of the United States, Commander SAMPSON, who spoke first, had put his views so clearly before the Conference that he (Professor ADAMS) would not detain it longer.

He would add, however, that if the Conference is to take a neutral meridian they must either erect an observatory on the point selected, which might be very inconvenient if they should choose such a point as is alluded to by the Delegate of France, or if some such place was not selected, we should merely have a zero of longitude by a legal fiction, and that would not be a real zero at all; that they would have to select their zero with reference to a known observatory, and that, for instance, supposing they took a point for zero twenty degrees west of Paris, of course that would be really adopting Paris as the prime meridian; that it would not be so nominally, but in reality it would be, and he thought that we now-a-days should get rid of legal fictions as much as possible, and call things by their right names.

Mr. JANSSEN, Delegate of France, said:

My eminent colleague, whose presence is an honor to this Congress, Professor ADAMS, thinks that I overlook too much the practical side of the question; namely, how a prime meridian can be established so as to cause the least inconvenience. He says that I pay too much attention to what he calls a question of sentiment, and he concludes by expressing the hope that all nations will lay aside their national pride and only be guided by this consideration: What meridian offers the greatest practical advantages? My reply is that I intend no more than Professor ADAMS to place the question upon the ground of national pride; but it is one thing to speak in the name of national pride and another to foresee that this sentiment common to all men, may show itself, and that we should avoid conclusions likely to arouse it, or we may compromise our success. That is all our argument; and the history of the great nation to which Professor ADAMS belongs furnishes us with examples of considerable significance, for the French meridian of Ferro was never adopted by the English, notwithstanding its happy geographical situation, and we all still awaiting the honor of seeing the adoption of the metrical system for common use in England.

But let us put aside these questions which I would not have been the first to touch upon, and place ourselves upon the true ground of the importance of the proposed reform, which is the only one worthy of ourselves or of this discussion. We do not refuse to enter into an agreement on account of a mere question, of national pride, and the statement of the changes and expenses to which we should have to submit in order to accomplish the agreement is a sufficient proof of this.

But we consider that a reform which consists in giving to a geographical question one of the worst solutions possible, simply on the ground of practical convenience, that is to say, the advantage to yourselves and those you represent, of having nothing to change, either in your maps, customs, or traditions--such a solution, I say, can have no future before it, and we refuse to take part in it.

Prof. ABBE, Delegate of the United States, stated that the Delegate of France, Mr. JANSSEN, had made a very important proposition to the Conference: That the meridian adopted should be a neutral one. He said that he had endeavored to determine what a neutral meridian is. On what principle shall the Conference fix upon a neutral meridian, and what is a neutral meridian? Shall it be historical, geographical, scientific, or arithmetical? In what way shall it be fixed upon? He looked back a little into the history of an important system adopted some years ago. France determined to give us a neutral system of weights and measures, and the world now thanks her for it. She determined that the base of this neutral system should be the ten-millionth part of a quadrant of the meridian. She fixed it by measurement, and to-day we use the metre as the standard in all important scientific work; but is that metre part of a neutral system? Is our metric system neutral? It was intended to be, but it is not; we are using a French system. Had the English, or the Germans, or the Americans taken the ten-millionth part of the quadrant of the meridian, they would have arrived at a slightly different measure, and there would have been an English, a German, and an American measure.

We are using the French metric system. It was intended to be a neutral system, but it is a French system. We adopt it because it deserves our admiration, but it is not a neutral system. The various nations of the world might meet and agree upon some slight modification of this metric system which would agree with the results of all scientific investigations, and thus make it international instead of French; but we do not care to do that, and are willing to adopt one system, taking the standard of Paris as our standard. How shall we determine a neutral system of longitude? The expression "neutral system of longitude" is a myth, a fancy, a piece of poetry, unless you can tell precisely how to do it. He would vote for a neutral system if the French representatives can tell the Conference clearly how to decide that it is neutral, and satisfy them that it is not national in any way.

Mr. JANSSEN, Delegate of France, said:

I perfectly understand the objection of my honorable colleague, Prof.

ABBE. He asks what is a neutral meridian, and adds that the metre itself does not appear to him to be a neutral measure, but to be a French measure. He relies upon the consideration that if the English, the Americans, and Germans, in adopting a definition of the metre, had measured it for themselves, they would have arrived each at a slightly different result, which would have given us an English, American, and German metre; nevertheless, he adds, we use the French metre, because we find it so admirable.

I would answer, first, that the metre, as far as the measure is derived from the dimensions of the earth, is not French, and it was precisely to take away this character of nationality that those who fixed on the metre sought to establish it on the dimensions of the earth itself. What is French is the particular metre of our national archives, which exhibits a very slight difference from that which our actual geodesy would have given us. Also, I think that if, at the time of the adoption of the Convention du Metre, in which the nations of Europe partic.i.p.ated, we had slightly changed the length of our standard to make it agree with the result of actual geodetic measurements, we should have done an excellent thing in depriving this measure of any shadow of nationality. I agree with my honorable colleague that if a few slight changes adopted by common accord could perfect the metrical system, we French ought to have no motive for opposing it. We have the honor of having invented a system of measures which, being based upon considerations of a purely scientific nature, has been accepted by all. Therefore if it can be said with truth that the metre of the Archives of Paris is French, (not intentionally, but because it bears the mark of an error of French origin,) it is an international metre, by the same t.i.tle that the discovery of the satellites of Mars made by my friend, Prof. Asaph Hall, whom I have the pleasure of seeing here, is scientific and of a universal nature.

The metre--equal to the ten-millionth part of the distance from the equator to the pole--is no more French than that distance itself, and, nevertheless, if the Americans, English, or Germans had measured it, they would each have arrived at a slightly different metre.

Now, my honorable colleague adds that a neutral meridian appears to him a myth, a fancy, a piece of poetry, so long as we have not exactly settled the method of determining it. I shall disregard the expressions which my honorable colleague has thus introduced into the discussion, because this discussion should be serious. It is plain that Prof. ABBE did not thoroughly apprehend the explanations which I gave of the proper methods of fixing the initial meridian, and of the conditions which make a meridian neutral; but I return to them, since I am invited to do so. Our meridian will be neutral if, in place of taking one of those which are fixed by the existing great observatories, to which, consequently, the name of a nation is attached, and which by long usage is identified with that nation, we choose a meridian based only upon geographical considerations, and upon the uses for which we propose to adopt it.

Do you want a striking example of what differentiates a neutral meridian from a national meridian? In order to avoid the confusion which existed in geography at the beginning of the seventeenth century, on account of the multiplicity of initial meridians then in use, a congress of learned men, a.s.sembled in Paris at the instance of Richelieu to select a new common meridian, fixed its choice on the most eastern point of the Island of Ferro. This was a purely geographical meridian, being attached to no capital, to no national observatory, and consequently neutral, or, if you please, purely geographical. Later, Le pere Feuillet, sent in 1724 by the Academy of Sciences to determine the exact longitude of the initial point, having given the figure 19 55' 3" west of Paris, the geographer, Delisle, for the sake of simplicity, adopted the round number 20; and, as I stated a little while ago, this alteration completely changed the character of this prime meridian. It ceased to be neutral, and became merely the meridian of Paris disguised, as has been truly said, and the English, notably, never adopted it. Here is the difference, gentlemen, between a neutral meridian and a national meridian.

And, parenthetically, you see, gentlemen, how dangerous it is to awaken national susceptibilities on a subject of a purely scientific nature. Now allow me to add that, if in 1633 it was possible to find a neutral meridian, a purely geographical meridian, an independent meridian, it may easily be done in 1884 if we wish to do so; and that a point chosen on purely geographical considerations, either in Behring's Strait or in the Azores, could be much better determined now than was possible to Father Feuillet in 1724, and could take the position which the meridian of Ferro would not have lost had it not been confounded with the meridian of Paris.

Professor J. C. ADAMS, Delegate of Great Britain, stated that he merely desired to refer to one subject touched on by the Delegate of France, Mr. JANSSEN, whose opinion he thought could hardly be supported, and that was that the question of longitude was purely one of geography. He desired to controvert that, and to hold that the question of longitude was purely one of astronomical observation. The difference of longitude between two places could not be determined by geodetic observations, because to do this you must take hypothesis as to the figure of the earth, and the figure of the earth is not a simple figure. You may take as hypothesis that the figure of the earth is spheroidal, and that the ratio of the axes is exactly defined. Now, in the first place, we are not agreed as to the exact ratio of the axes, nor are we agreed as to the exact figure of the earth. If an attempt is made to measure the difference of longitude between two points on the earth's surface, especially when they are a considerable distance from each other, it is necessary to depend upon astronomical observations. In attempting to deduce the difference of longitude from geodetic measures, you must a.s.sume that the true figure and dimensions of the earth are known, which is far from being the case. The theory that the prime meridian is a matter purely of a geographical nature is liable to the fatal objection that the determination of the difference of longitude between one place and the other is really the determination of the difference of time of the pa.s.sage of a star across the meridian of the two places concerned. That is very definite. You observe the transit of the star at one place, and you observe the transit of the star at the other place, and by means of telegraphic communications you are able to determine their difference of longitude independent of the figure of the earth. He said, in conclusion, that he thought the honorable Delegate of France was mistaken upon the main point which he had just referred to, if, indeed, he had rightly understood him.

M. JANSSEN, Delegate of France, replied as follows:

I think that M. ADAMS entirely misunderstands me. I agree with him absolutely in thinking that longitudes cannot be determined, especially of places far apart, except by astronomical methods.

Geodesy can only furnish it for short distances; in such cases, it is true, it supplies it with a degree of accuracy which meridia.n.a.l observations cannot attain. So, if the question be to determine rigorously the difference of longitude in time between two places on the earth at considerable distances apart, it becomes one of astronomy, because here it is astronomy which gives the quickest and most accurate solution. For these reasons if, for instance, we should wish to connect a given observatory with a point situated on the other side of the ocean which had been chosen as the starting point of longitudes, it would become a question of astronomy. Astronomy here is an admirable instrument for the solution, but it should only be the instrument.

On the contrary, the question becomes geographical, if it be that of determining where it will be most convenient to fix the origin of terrestrial longitudes. If the question be, for instance, to select one or another point, in some one or other ocean, astronomy has nothing to do with it, and when it wishes to impose upon us one of its observatories to fulfil such a function it tends to give an inaccurate solution.

At first sight it may seem that any point might become a starting point for terrestial longitudes, but when we study the question a little more we see there may be great advantages in choosing some one point in preference to some other. Hence it is that all geographers have agreed to place initial meridians, when possible, in the oceans.

The PRESIDENT stated that, in accordance with the decision of the Conference, he had sent to the scientists named by them invitations to a seat upon this floor. The Chair sees several of these gentlemen here to-day, notably one of the most eminent astronomers of this country, to whom his countrymen are always ready to do homage, Professor Newcomb, Superintendent of the United States Nautical Almanac. If it be the pleasure of the Congress, the Chair will now request Professor Newcomb to give us his views upon the resolution now under discussion.

No objection being made to the proposition of the President, Professor NEWCOMB arose and said:

That in reference to the remarks of the distinguished Delegate of France, Professor JANSSEN, he would prefer, if the Conference would consent, to study his arguments more carefully when they should be in print.

He remarked that some points raised by that argument have been already replied to, and he wished now more particularly to request that Professor JANSSEN would define precisely what he meant by "a neutral meridian;" that he had partially answered this question in reply to Professor ABEe; but that there was a more fundamental point, one of practice, which must be brought in and kept in mind at every step, and which was raised by Commander SAMPSON'S paper, to which he had listened with great interest. Commander SAMPSON held that it would be necessary to have a fixed observatory on the chosen prime meridian, but he (Professor NEWCOMB) did not concur in that view, but rather agreed to a limited extent with what Professor JANSSEN had said on that question.

In choosing a meridian from which to count longitude, you meet a difficult problem. You have a point on the globe defined as the first meridian. This would be taken as the initial point of departure, and you are to determine the longitude of a certain place from that point.

Now, doubtless, there is no other way to do this than to have an astronomical instrument and telegraphic communication. And if they chose the Azores or Behring's Strait, in neither case could they mount a transit instrument or have a system of telegraphic communication.

Nor could we make a determination of longitude from a single fixed observatory in any case.

He then stated that it was impracticable under any circ.u.mstances to have an absolutely neutral prime meridian; that the definition of the prime meridian must practically depend upon subsidiary considerations, no matter where it might be located. In the practical work of determining longitudes a connection with the prime meridian cannot be made in each case. What is really determined is the longitude from some intermediate point, generally in the same country, and in telegraphic communication with the place whose longitude we wish to know. This intermediate point would, for the time, be the practical prime meridian. But the longitude of this point itself must always be uncertain. Science is continually advancing in accuracy, and we find that we continually need to correct the longitude of our intermediate meridian, and hence of all points determined from it. How can this difficulty of constantly changing longitudes be avoided? He replied that each system of connected longitudes must rest upon its own basis.

It must be referred to an a.s.sumed prime meridian, and the measurements must be made from that, even if it be found to be somewhat in error. If some such system had been adopted thirty or forty years ago, we would have avoided the confusion arising from the fact that the longitudes given on many maps do not refer at all to any absolute meridian. All that is known is that the astronomers determined the longitude of the place, and then the maps had to be corrected accordingly. The longitude of one place would be determined from Cambridge, and perhaps in the neighborhood is another place determined from the observatory at Washington. In either case we know nothing of the longitude of Cambridge or Washington which the observer a.s.sumed in his calculations.

Generally, in determining longitude, the country adopts the princ.i.p.al place within its confines as a subsidiary prime meridian, and the a.s.sumed longitude of this place is necessarily selected somewhat arbitrarily. The longitude, for instance, of Washington was, thirty years ago, known to be nearly 5 hours 8 minutes and 12 seconds west from Greenwich. Had we adopted this difference by law, it would have amounted to choosing for our prime meridian a point 5 hours 8 minutes and 12 seconds east of Washington, whether we happened to strike the transit instrument at Greenwich or not. This would have fixed an a.s.sumed longitude for the Cambridge observatory and for all points within our telegraphic net-work. We should have had a practical system, which might, however, require to be corrected from time to time, if some slight error were found in the a.s.sumed longitude of Washington.

In the present state of astronomical observation these little errors are of no consequence except in some very refined astronomical discussions. For all geographical and perhaps geodetical purposes the error may be regarded as zero, and it may be said, in regard to astronomical work, that it will always be independent of any meridian that might be chosen.

But even if this difficulty were avoided, he could not see how they could have any place which would come within the definition of a neutral meridian. Supposing they took the Azores, they belong to Portugal; then certainly they would have a Portuguese prime meridian, belonging to the Portuguese nation. Thus they would no longer have a neutral point, if he (Professor NEWCOMB) rightly understood the meaning of Professor JANSSEN.

He said that the Delegate of Great Britain, Professor ADAMS, had expressed very clearly his (Professor NEWCOMB'S) ideas, and the difficulty we have in meeting the propositions of the French Delegates; that what he had said would apply very properly to any neutral meridian that might be chosen in accordance with the plans of Professor JANSSEN. Whatever that meridian might be, we must always a.s.sume for it a certain number of degrees from the capital of the country, where the place to be determined is located, and then take that imaginary meridian instead of a real point on the surface of the globe.

It is true that this is perfectly practicable, and on that theory there might not be any necessity of having an astronomical observatory. But why we should go to this trouble and expense Mr.

JANSSEN did not make very clear; his considerations were purely sentimental, as was remarked by the Delegate of Great Britain, Professor ADAMS, and he (Prof. NEWCOMB) did not see what advantage would be gained by a neutral meridian in preference to one fixed by convenience.

In order that a discussion may proceed, it is necessary to agree on a given basis from which to start, and it is extremely difficult to agree upon a basis if there are considerations of sentiment introduced, because such considerations are peculiar to each person.

He therefore wished to propose this question again to the Delegate of France, namely, what advantages can we derive from fixing upon a neutral meridian?

Mr. JANSSEN, Delegate of France, said:

Professor NEWCOMB asks me to point out the advantages of a neutral meridian. These advantages are of two kinds--they are of a geographical nature and a moral nature. Let us examine the first. By placing the initial meridian between Asia and America, we get away from the centres of population, which is almost indispensable in view of the change of dates. We divide the world into two parts, the Old World and the New. The advantage of drawing the prime meridian through the ocean has always been understood, and it was precisely for this reason that Marinus of Tyre, during the first century, placed it at the Fortunate Isles, west of the African Continent. It is idle to urge the difficulty of fixing such a meridian as an objection.

Astronomy is so far advanced in our day as to enable us to make this calculation with all desirable accuracy.