fToi- v.. Bo. a
��I
��e 14, for 'distortiunal ' aubsUtuLe 'cm ^xpreBBiona for ^, eiTen i eqaallon (IT), Insert ' tan i ' before
��P. 69, li densationi P. 206, in llie tn-o <
��tn the expression for
tlon (£0), insert ' [an 1 ' before
roula fruni whlcli these exprei
��"%' -
��U'+l
��deduced is
��correctly given at the foot of p. 2115.
P. 29<l, ill line 13 from top of the page, abd in the left-hand niemiwrs of equations (20) and (21), for ' id' and ' to,,' read ' u' ami 'u,' respectively.
William Thomson.
Tbe nnlccnlly. Qluspiw. Unrofa S«.
The oold ^-eather of Febmarjr and Maiob. During the past two months the cold weather has been of unusually long duration ; bo much so, that in many places in and about the city the water and gas pipes, which are placed about four feet under the ground, have been frozen. This being tbecase, I have thought that It would be Interesting to see, from the records of Draper's continuous self-recording ther- mometer of this observatory, what was the difference in the duration of the cold in this year, as compared with last. The following table shows the comparison of temperature every ten degrees, from the lowest to tbe highest, for the years 1S84 and lS8o, during the months of Februair and Uarch, and also the number uf times or hours the temperature was below or above 80°, wblcb has tieen taken as a temperature of neither freezing nor thawing.
�� �1SB4.
�1S8..
� �llomi-diinUoD.
�tionn' dalKtlDD.
� �f-brwy.
�IbriA.
�Mn>»i.
�Mareb.
�-lOlo
IB to SO i ' '. '.
aowM
�U
at)
�106
�lU
�ISO
�HannofMid . .
�HI
�18T
�U1
�»1
�aotoM
tOloBD .'
flnioTD
�18
�333
102
�M
�tm
�HoanofbHt . .
�S»
�HT
�lU
�*" ,.
��Hognofooldi In ISSA.fbrUHreb . . . . ! ^ ! ! SOI TBI BoDnof eold. Id 1M4. for FsbrtiUT , 141
Hi>aniir«>1d,ln1SS4,for March IRT 328
DUrersnceorhuiinofrDldlwtwHnthetwoyun . . . . 4aO " There were therefore, during these two months, 4(10 hours more of cold in 1BS5 than in 1884.
Daniel Draper, Ph.D.,
BlffCtoT.
��CIVIL AND ASTRONOMICAL TIME.
Thekg seems to be a good deal of doubt whether the roeommendations of the Prime-me- ridian conference are going to be very gener-
��ally accepted. France, and the natiooa a French influence, certaialy nill not adopt tl new anti- Greenwich meridian for many year if ever. The matter is really one of com- paratively little im|)ortatice ; that is to say, % will make no very great practical difference t( any one if different nations continue U) UK different meridiuDB : still there can b« u. question that there would be a real and coiK siderable convenience in the eslabltshmcnt oT a single meridian, and consequently of a tiaifr^ system, which, like our present raiiroad-d in the United States, would be identical as to minutes and seconds all over the earth. probable that the gentle pressure of this COB^ venienee will, after a while, bring about ll* desirable concurrence, especially as the ii creasing extent and rapidity of travel and cot munication will all the time bring out mo forcibly the inconveniences of the present state of affairs, and tend to weaken mere local feeling and prejudice, which, afler all, main obstacle at praaeut to the univendi adoption of the meridian proposed.
The recommendation that astro nomeil should come into agreement with other falkkr and begin their day at niduigbt instead a the following noon, as at present, seems cspl cially likely to fail. The Greenwich obserM tory, iniieed, adopted the new plan on Jan. I but, so far as we know, no other imporUA astronomical establishment has j'et done H Commodore Franklin, of the U. S. naval dA servatorj', proposed to follow the example 4 Greenwich, and issued an order to that effect but it excited so much opposition from cci tain eminent and influential astronomers, thi the order was suspended before the time can for it to go into operation.
The objections of Professor Newcomb, wl has formulated more fully and forcibly Uq any one else the reasons why the cbai| should not be made, relate not so much to ih fact that astronomers would find it inconvsl lent to change the date of their obser^'atlol at midnight, as to the confusion that would | likely to result in the combination and compH ison of observations taken before the introdOl
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