International Conference Held at Washington Part 15

With regard to the reckoning of longitude, I submit that longitude and time are so intimately related that they may be expressed by a common notation. Longitude is simply the angle formed by two planes pa.s.sing through the earth's axis, while time is the period occupied by the earth in rotating through that angle. If we adopt the system of measuring time by the revolution of the earth from a recognized zero, one of these planes--that through the zero--may be considered fixed; the other--that through the meridian of the place--being movable, the longitudinal angle is variable. Obviously the variable angle ought to be measured from the fixed plane as zero, and as the motion of the earth by which the equivalent time of the angle is measured is continuous, the longitude ought to be reckoned continuously in one direction. The direction is determined by the notation of the hour meridians, viz., from east to west.

If longitude be so reckoned and denoted by the terms used in the notation of cosmic time, the time of day everywhere throughout the globe would invariably denote the precise longitude of the place directly under the mean sun. Conversely, at the epoch of mean solar pa.s.sage at any place, the longitude being known, cosmic time would be one and the same with the longitude of the place.

The advantages of such a system of reckoning and nomenclature, as suggested in the recommendations which I now submit, will be, I think, self-evident.

RECOMMENDATIONS FOR THE REGULATION OF TIME AND THE RECKONING OF LONGITUDE

1. _That a system of universal time be established, with the view of facilitating synchronous scientific observations, for chronological reckonings, for the purpose of trade and commerce by sea and land, and for all such uses to which it is applicable._

2. _That the system be established for the common observance of all peoples, and of such a character that it may be adopted by each separate community, as may be found expedient._

3. _That the system be based on the principle that for all terrestrial time reckonings there be one recognized unit of measurement only, and that all measured intervals of time be directly related to the one unit measure._

4. _That the unit measure be the period occupied by the diurnal revolution of the earth, defined by the mean solar pa.s.sage at the meridian twelve hours from the Prime Meridian established through Greenwich._

5. _That the unit measure defined as above be held to be a day absolute, and designated a Cosmic Day._

6. _That such Cosmic Day be held as the chronological date of the earth, changing with the mean solar pa.s.sage at the anti-meridian of Greenwich._

7. _That all divisions and multiples of the Cosmic Day be known as Cosmic Time._

8. _That the Cosmic Day be divided into hours, numbered in a single series, one to twenty-four, (1 to 24,) and that the hours be subdivided, as ordinary hours, into minutes and seconds. Note.--As an alternative means of distinguis.h.i.+ng the cosmic hours from the hours in local reckonings, they may be denoted by the letters of the alphabet, which, omitting I and V, are twenty-four in number._

9. _That until Cosmic Time be admitted as the recognized means of reckoning in the ordinary affairs of life, it is advisable to a.s.similate the system to present usages and to provide for the easy translation of local reckonings into Cosmic Time, and vice versa; that, therefore, in theory, and as closely as possible in practice, local reckonings be based on a known interval in advance or behind Cosmic Time._

10. _That the surface of the globe be divided by twenty-four equidistant hour meridians, corresponding with the hours of the Cosmic Day._

11. _That, as far as practicable, the several hour meridians be taken according to the longitude of the locality, to regulate local reckonings, in a manner similar to the system in use throughout North America._

12. _That, in all cases where an hour meridian is adopted as the standard for regulating local reckonings, in a particular section or district, the civil day shall be held to commence twelve hours before and end twelve hours after the mean solar pa.s.sage of such hour meridian._

13. _That the civil day, based on the Prime Meridian of Greenwich, shall coincide and be one with the Cosmic Day.

That civil days on meridians east of Greenwich shall be (according to the longitude) a known number of hours, or hours and minutes in advance of Cosmic Time, and to the west of Greenwich the contrary._

14. _That the surface of the globe being divided by twenty-four equidistant meridians (fifteen degrees apart) corresponding with the hours of the Cosmic Day, it is advisable that longitude be reckoned according to these hour meridians._

15. _That divisions of longitude less than an hour (fifteen degrees) be reckoned in minutes and seconds and parts of seconds._

16. _That longitude be reckoned continuously towards the west, beginning with zero at the Anti-prime meridian, twelve hours from Greenwich._

17. _That longitude, generally, be denoted by the same terms as those applied to Cosmic Time._

I submit these recommendations suggestively, and without any desire unduly to press them. I shall be content if the leading principles laid down be recognized by the Conference.

With regard to the more immediate question, I have come to the firm conviction that extreme simplicity of reckoning and corresponding benefits would result if longitude be notated in the same manner, and denoted by the same terms as universal time. If, therefore, the Conference adopts the motion of the distinguished Delegate of the United States, which, I apprehend, is designed to cause as little change as possible in the practices of sea-faring men, I trust the claims of other important interests will not be overlooked. I refer to all those interests, so deeply concerned in securing accurate time on land, and in having easy means provided for translating any one local reckoning into any other local reckoning, or into the standard universal time. In this view I trust the Conference will give some expression of opinion in favor of extending around the globe the system of hour meridians which has proved so advantageous in North America. In an educational aspect alone it seems to me important that the hour meridians, one to twenty-four, numbered from the anti-prime meridian continuously toward the west, should be conspicuously marked on our maps and charts.

Prof. ADAMS, Delegate of Great Britain. I wish, Mr. President, to express my entire adhesion to the proposition which has been made by the Delegate of the United States, Mr. RUTHERFURD. It seems to me to satisfy one of the princ.i.p.al conditions that we have had before us to guide our decision; that is, that we should pursue a course which will produce the least possible inconvenience.

Now, I think if we keep that in mind, we shall have very little difficulty in coming to the conclusion that we should reckon longitude eastward, as positive or plus, and westward as negative or minus. This mode of reckoning would be attended with the least inconvenience; in fact, it will not be attended with any inconvenience at all, because it will keep to the present mode of reckoning. For my part, I see no adequate reason for changing that. There is no scientific reason, and certainly there is no practical reason. There is no scientific reason, because, as I stated yesterday, if in mathematics you measure from the zero a distance in one direction and consider that positive, you must, by the very nature of the case, consider the distance measured in the opposite direction from the same zero as negative. One follows mathematically and necessarily from the other, and by adopting this resolution you thus include both in one general formula.

It seems to me quite as scientific, to say the least, to start from zero and go in both directions, distinguis.h.i.+ng the longitudes by the signs plus and minus, according as the directions are taken east or west, as to reckon longitudes in one direction only from zero to 360 degrees. It is, I say, just as scientific to do this, and practically it is more convenient. Because if you go on reckoning from zero to 360 degrees continuously, you have to make a break at 360 degrees. You do not count on after you have completed one revolution, but have to drop the 360 degrees and start again at zero. But this is attended with great inconvenience, because this break in counting occurs in countries which are thickly inhabited. The longitude would be a little less than 360 degrees on one side of the prime meridian, and on the other side the longitude would be a small angle. This seems to me very inconvenient.

On the other hand, if you count longitudes in one direction from zero to 180 degrees as positive, and in the opposite direction from zero to 180 degrees as negative, you are, no doubt, obliged to make a break in pa.s.sing abruptly from plus 180 degrees to minus 180 degrees. But the break would then occur where it would cause the least inconvenience, viz., in mid-ocean, where there is very little land and very few inhabitants, and where we are accustomed to make the break now. This will require no change in the habits and customs of the people, and no inconvenience whatever would be caused by the action of the Conference if it decides on this method, which also has the minor advantage of not requiring the use of such large numbers as the other. But to adopt the reckoning of longitude from zero to 360 degrees would involve a very considerable change, and I think it may be doubted whether it would be generally accepted. Under the circ.u.mstances, I think the resolution contains the most expedient course for us to adopt. I do not object to anybody who chooses to do so reckoning on, for certain purposes, from zero to 360 degrees, but I do not think it would be well to make it compulsory.

With regard to the proposal of the Delegate of Great Britain, Mr.

FLEMING, I would say that it would be attended with great inconvenience, because it departs from the usages and habits now existing. That, to my mind, is a very great and insuperable objection, and I do not see any countervailing advantage.

With regard to the subject of time that Mr. Fleming is anxious to take into consideration, I think that nothing can be simpler, if I may be allowed to deal with the question of time, than the relation between time and longitude which is proposed to be created by the resolution of Mr. RUTHERFURD.

By that resolution the longitude indicates the relation between the local time and the universal time in the simplest possible way. What can be easier than the method involved in the resolution of Mr.

Rutherfurd? It is this: Local time at any place is equal to universal time plus the longitude of the place, plus being understood always in a mathematical sense. The longitude is to be added to the universal time if it is positive, and subtracted if it is negative. That is very simple, the whole being involved in one general formula.

Now, I think it is perfectly impossible for Mr. Fleming to make a more simple formula than that. The formula laid down in the proceedings of the Roman Conference was far less simple, as it involved an odd twelve hours. You got the universal time equal to the local time, minus the longitude, plus twelve hours. This is far from simple. It makes the calculation more complicated, and it seems to me that for other reasons it is objectionable.

Mr. RUTHERFURD, Delegate of the United States. Mr. President, I do not propose to take up the time of the Conference in reiterating the very conclusive remarks in favor of this resolution made by the Delegate of Great Britain. I wish, however, to allude, for a moment, to another view of this question. Suppose we do not adopt this resolution. What is the course before the Conference? We shall then be called upon, no doubt, to decide that longitude shall be counted all around the world from zero to 360 degrees.

That general proposition is one which would not probably meet with violent opposition, but the next point is one that will divide us very materially, and perhaps disastrously. Which way shall we count? Shall it be towards the east or towards the west?

My conversations with the gentlemen here present have lead me to know that there is a very great difference of opinion upon this point, and I believe that if we should not adopt this resolution and should decide to count longitude from zero to 360 degrees, a preference to count it in one direction rather than the other would be established only by a very close vote, nearly annulling the whole moral influence of the Conference, and we should go back to our Governments without much, if any, authority on the point in question.

And I doubt whether our resolutions would be accepted by these Governments if we show ourselves to be divided upon a question of so much practical importance.

It is simply a question of practice--of convenience. We all bowed to the rule of convenience in selecting the meridian of Greenwich. And why? Because seven-tenths of the civilized nations of the world use this meridian, not that it was intrinsically better than the meridian of Paris, or Was.h.i.+ngton, or Berlin, or St. Petersburg. n.o.body claimed any scientific preference among these meridians. It was simply because seven-tenths of the civilized world were already using the meridian of Greenwich.

If we accept this argument in favor of the first resolution for selecting the initial meridian, why should we not be equally inclined to recognize the fact that all the civilized world count longitude in both ways? There is no difference of opinion on that point. There is no difference of usage. Shall we break that usage? Shall we introduce a new system, which may or may not be found practical or agreeable?

Shall we not rather adopt the rule of all nations, already in use among their practised astronomers and navigators, by saying continue to do as you have already done?

Sir FREDERICK EVANS, Delegate of Great Britain. Having for many years mixed among the practical seamen of more than one nation, I confess I look with some dismay on any other system for the notation of longitude being adopted than the one proposed in this resolution.

My colleague, Mr. FLEMING, made the remark that he could not disa.s.sociate longitude from time. If he had mixed with seamen, he would have found out that there is very frequently a well-defined difference between the two in their minds. Longitude with seamen means, independently of time, s.p.a.ce, distance. It indicates so many miles run in an east or west direction. Consequently, I am not able to look upon longitude and time as being identical.

Under these circ.u.mstances, this resolution also, as I understand it, should be considered on practical grounds.

The question of universal time will come on for consideration hereafter, and how that may be settled seems to me a matter of indifference compared with the decision on this resolution. I question, for myself, whether any other plan than that it proposes would be generally accepted. That is what I am afraid of. Whatever respect nations may have for this Conference, public opinion would be very strong upon the point now at issue. When you further recollect that all around the globe, in all these various seas, there are colonies with histories; that their geographical positions and boundaries were originally recorded by longitude according to the notation of which I have spoken, I think it is to be over sanguine to expect that those colonies will accept a new notation of longitude without greater proof of the positive necessity of the change. It would not be the fiat of this Conference, or the fiat of any government, that would bring about the change. I say this with all deference to the opinions of those who have advocated a change.

General STRACHEY, Delegate of Great Britain. At the risk of repeating somewhat my remarks made to the Congress when we last met, I would add a few words to what has now been said. It is our wish that the points of real difference should, as far as possible, be clearly brought out before the Conference comes to a vote.

As regards the counting of longitude in two directions, and the degree of advantage or disadvantage that may arise in starting from zero and treating east longitude as positive or plus, and west longitude as negative or minus, let me ask the attention of the Congress to the fact that longitude is already counted in these two directions, and that, as a matter of fact also, lat.i.tude is counted in the same way, in both directions from the equator, north lat.i.tude being plus and south lat.i.tude minus. n.o.body, so far as I have heard, has ever proposed that we should abolish this method of reckoning lat.i.tude, and subst.i.tute for it North or South polar distance, to be counted right round the earth; and yet there is the same _quasi_ scientific objection to the present method of counting in the one case as in the other. As already stated, it seems to me that, for purposes of practical convenience, it is extremely difficult, if not impossible, to separate the ideas on which the reckoning of longitude must be based, from those which must regulate the reckoning of time, and especially the reckoning of time in the sense of adopting a universal day over the whole world. Now, it appears to me that, as regards the acceptance of the universal day, it certainly will be anything but convenient, if it begins and ends otherwise than when the sun pa.s.ses the 180th meridian. On the contrary, I think it will be extremely inconvenient. I think that if the world were to adopt the meridian of Greenwich as the origin of longitude, the natural thing for it to do would be to have the international day, the universal day, begin from the 180th meridian from Greenwich--that is, to coincide with the Greenwich civil day. That meridian pa.s.ses, as I said before, outside of New Zealand, and outside of the Fijee Islands; it goes over only a very small portion of inhabited country. It appears to me, therefore, that inasmuch as there must be an absolute break or discontinuity in time in pa.s.sing round the earth--a break of twenty-four hours--it is much more convenient that this break should take place in the uninhabited part of the earth than in the very centre of civilization.

If we adopt the universal day which coincides with the civil day at Greenwich, then you will be able to have complete continuity of local time over the whole earth, in harmonious relation with the universal day, except at the break which necessarily takes place on the 180th meridian. Otherwise this will not be possible. For instance, according to the system proposed by the resolution, the local time corresponding, say, to 0 hours of Monday at Greenwich, would, in pa.s.sing round the earth to the eastward from the 180th meridian, gradually change from 12 hours of Sunday to 12 hours of Monday; and, on returning to that meridian, the break of time would occur, and one day would appear to be lost. But complete continuity both in the days and hours, and harmony with the universal day, that is, the Greenwich civil day, would be preserved for the whole earth, excepting on crossing the 180th meridian.

The result of the system which was proposed at Rome would be to cause the break of dates to take place at Greenwich at noon, so that the morning hours of the civil day would have a different universal date from the afternoon hours, and this would be the case all over Europe.

But if the universal day be made to correspond to the civil day of Greenwich, and the longitude is counted east in one direction and west in another direction to the 180th meridian, these difficulties would be overcome, and a perfectly simple rule would suffice for converting local into universal time. As regards what was said upon the subject of longitude being plus or minus, according as you move to the east or west, it appears to me that there is a positive, clear, and rational reason for calling longitude eastward plus and longitude westward minus. The time is later to the east, and therefore the hour is indicated by a higher number. In converting universal into local time, if the place is east of Greenwich, you add the longitude to the universal time, and therefore increase the number of the hour; if the place be west of Greenwich, you subtract the longitude, and therefore diminish the number of the hour. It is natural, therefore, to call east longitude positive and the other negative.

It appears to me also that the pa.s.sage of the sun over the meridian is, in reality, what may be called the index of the day, the day consisting of 24 hours, distributed equally on either side of the meridian. Noon of the universal day would thus coincide with the time of the sun pa.s.sing the initial meridian. There is perfect consistency, therefore, in adopting the reckoning of longitude and time that is proposed in the resolution before us. It is a rational and symmetrical method.

Mr. JUAN PASTORIN, the Delegate of Spain. I listened with great pleasure to the observations which our honorable colleague, the Delegate of England, General STRACHEY, has just made.

I am not sufficiently acquainted with the English tongue to make a speech, though I know it well enough to follow the debate. Moreover, as I had beforehand studied the subject which is now before us, I have quite well understood all that has been said on this point. I proposed an amendment yesterday, in order to obtain what I consider the most simple formula for converting local time into cosmical time. This formula is not, perhaps, the most suitable for astronomers and sailors, but they form the minority, and it is, I am sure, the easiest for the ma.s.s of the people. This formula would be based on the considerations which are now under discussion. I am not sufficiently familiar with the language to give the reasons upon which I based my amendment, but, as I demonstrated in the pamphlet which I had the honor of addressing to my learned colleagues, the means, in my opinion, of obtaining the simplest and the most suitable formula is to make the beginning of civil time and of dates on the first meridian coincide with the cosmical time and date, and to count longitude continuously in the same direction from the initial meridian. This is what I proposed to obtain by my amendment.