314 TRANSACTIONS OF THE CANADIAN INSTITUTE. [ Vou. IONE 
precepts and methods laid down in his text books. . . . But this would only be 
the beginning of the confusion. Astronomical observations and ephemerides are made 
and printed not only for the present time, but for future generations and for future 
centuries. If the system is changed as proposed the astronomers of future generations 
who refer to these publications must bear the change in mind in order not to misinter- 
pret the data before them. The case will be yet worse if the change is not made by all 
the ephemerides and astronomers at the same time epoch. It will then be necessary 
for the astronomers of the twentieth century, using ephemerides and observations of the 
present, to know, remember, and have constantly in mind a certain date different in 
each case at which the change was made. For example, if, as is officially announced, 
the Naval Observatory introduces the new system on January 1, 1885, then there will be 
for several years a lack of correspondence between the system of that establishment and 
the system of the American Ephemeris, which is prepared four years in advance. 
I see no advantage in the change to compensate for this confusion. If astro- 
nomical ephemerides were in common use by those who are neither navigators nor 
astronomers the case would be different. But, as a matter of fact, no one u es these 
publications except those who are familiar with the method of reckoning time, and the 
change from astronomical to civil time is so simple as to cause no trouble whatever. 
The change will affect the navigator as well as the astronomer. Whether the 
navigator should commence his day at noon or midnight, it is certain that he must 
determine his latitude from the sun at noon. The present system of counting the day 
from noon enables him to do this in a simple manner, since he changes his own noon 
into the astronomical period by the simple addition or subtraction of his longitude. 
To introduce any change whatever into the habits of calculation of uneducated men is 
a slow and difficult process, and is the more difficult when a complex system is to be 
substituted for a simple one. I am decidedly of the opinion that any attempt to 
change the form of printing astronomical ephemerides for the use of our navigators 
would meet with objections so strong that they could not be practically overcome. 
_. I respectfully submit that in view of these considerations no change should be 
made in the change of reckoning time employed in the publications of this office until, 
by some international arrangement, a common date shall be fixed by all nations for the 
change.—Argument against changing the Astronomical Day, by Prof. S. Newcomb, 
LLD., Etc., Superintendent of the Nautical Almanac Office, Washington, Dec. 6, 1884. 
V. Referring to the letter of Professor Newcomb, concerning the resolution of the 
late International Meridian Conference on the subject of the change of the astronomi- 
cal date, so as to make the midnight of Greenwich o hours, instead of noon as at present, 
I have the honor to submit the following considerations. . . . The order referred 
to was not issued without a knowledge on my part of the views of such a distinguished 
astronomer as Professor Adams, of England, as well as of those of other members of 
the Conference. A reference to the proceedings of the Conference shows that its 
recommendation on this point was unanimous. It has been publicly announced in 
Nature that the Astronomer Royal of England proposes to make the change,on the 
same date as that directed by me; this has been confirmed by a telegram received 
from him by me. So far as the counting of astronomical time from antiquity is con- 
cerned, it is the argument of conservatism which desires no change in an existing 
