February, is(>5.] Hotv to Determine Time at the Pole. 141 



lu Chapel's thermometer the mercury would not run down the tube while 

 inverted until a few degrees of warmth were communicated to it, ])ut Uw, ther- 

 mometer continued to act. I am sati«tied that a good mercurial instrument will 

 indicate the true state of the atmosphere several degrees below the temperature 

 of the mercury with which it is filled. 



In one of liis leisure hours, revolving in mind the problem f>f 

 determining time at the North Pole, he came to the conclusion that 

 with the helj) of an English nautical almanac, Greenwich time could be 

 found there by star occultations or by the eclipses of Jupiter's satel- 

 lites, but perhaps oftener b}^ lunar distances. He had at first reasoned 

 that at a place where there could be no such thing as a day, and no 

 cardinal point but one ; where all the lieavenly bodies revolve paral- 

 lel to the horizon, with the exception of the change caused b}' the 

 variation of declination ; where there is no meridian, or rather where 

 every meridian is : — it would seem impossible to determine time. 



* There is one great difficulty that will be experienced bywhomsoever shall reach the Pole; 

 that is, there will ie no means for detcrmhihig time by astronomical ohservations. How can there be 

 "when all the heavenly bodies in view of the observer while at the Pole are continually revolving 

 about him parallel with his horizon. The only exception to this is simply the variation of decli- 

 nation. At the Korth Pole there can be no tq^per or loiver culminations of the sun, moon, planets, 

 and stars, for it is a point where there is no meridian; then it follows that there is no day there — 

 no solar day, no siderial day, no lunar day. W^hy no day ? "Because a day is the interval time 

 between the departure of a heavenly body from any meridian and its succeeding return to it ;" 

 and there being no meridian at the North Pole, there can be no departure from or return to one by 

 a heavenly body. At the North Pole there is no meridian ; it is a point nevertheless where the 

 meridians of every spot on the face of the globe meet, or, in other words, where they terminate 

 to (zero or nothing). But a new idea had just struck me. Time can be determined at the North 

 Pole by lunars. Having a Nautical Almanac and the usual instrnments, it can be easily done. 

 Take one observation of the sun's altitude, or of either of the planets or stars used in lunar obser- 

 vations; one altitude of the moon, without any particular care in noting the exact time when 

 these two observatiens are made ; then carefully observe the angular distance of sun and moon, 

 or moon and one of the planets or stars used in lunar observations, and note the time. 



[I did not mean by my references to determining time at the Polo that this will be North 

 Polar time or mean time. Certainly not, for this, as I understand the matter, would be absurd. 

 To say that such an event occurred at such an hour North Pole time or mean time would be out of 

 all reason]. 



Having made the usual observations in taking a lunar, Avork these up. The true distance 

 of the moon from sun, or planet, or star being found, proceed with the use of the lunar tables as 

 in lunar work. The result will be Greenwich time if the British or American Nautical Almanac 

 be the one used. I do not consider it necessary that one at the Pole should have a chronometer 



