308 



SCIENCE. 



[Vol. V., No. 115. 



P. 59, line 14, for ' distortion al ' substitute 'con- 

 densational.' 

 P. 296, in the two expressions for V ; » given in 



<(^-l)s 



equation (17), insert ' tan i ' before 



(£ + 1 



also 



in the expression for 'tane' and 'tane l5 ' of equa- 



'(/i 2 — l) 2 ' 

 tion (20), insert ' tan i ' before 2 , -, • The for- 

 mula from which these expressions are deduced is 

 correctly given at the foot of p. 295. 



P. 296, in line 13 from top of the page, and in 

 the left-hand members of equations (20) and (21), for 

 * w ' and '«)],' read 'w' and 'w/ respectively. 



William Thomson. 



The university, Glasgow, March 26. 



The cold weather of February and March. 



During the past two months the cold weather has 

 been of unusually long duration ; so 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 the case, 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 

 the highest, for the years 1884 and 1885, during the 

 months of February and March, and also the number 

 of times or hours the temperature was below or above 

 30°, which has been taken as a temperature of neither 

 freezing nor thawing. 





1884. 



1885. 



Degrees. 



Hours' duration. 



Hours' duration. 





February. 



March. 



February. 



March. 



-10 to 



to 10 



10 to 20 



20 to 30 



14 

 30 



97 



11 



71 



105 



44 

 191 

 250 



5 

 139 

 157 



Hours of cold . . 



141 



187 



487 



301 



30 to 40 



40 to 50 



50 to 60 



60 to 70 



375 

 152 



28 



223 

 225 

 102 



7 



155 



30 



362 

 62 

 19 



Hours of heat . . 



555 



557 



185 



443 



Hours of cold, in 1885, for February 487 



Hours of cold, in 1885, for March 301 788 



Hours of cold, in 1884, for February Ill 



Hours of cold, in 1884, for March 187 328 



Difference of hours of cold between the two years .... 460 



There were therefore, during these two months, 460 

 hours more of cold in 1885 than in 1884. 



Daniel Draper, Ph.D., 



Director. 



CIVIL AND ASTRONOMICAL TIME. 



There seems to be a good deal of doubt 

 whether the recommendations of the Prime-me- 

 ridian conference are going to be very gener- 



ally accepted. France, and the nations under 

 French influence, certainly will not adopt the 

 new anti-Greenwich meridian for many years, 

 if ever. The matter is really one of com- 

 paratively little importance ; that is to say, it 

 will make no very great practical difference to 

 any one if different nations continue to use 

 different meridians : still there can be no 

 question that there would be a real and con- 

 siderable convenience in the establishment of 

 a single meridian, and consequently of a time- 

 system, which, like our present railroad-time 

 in the United States, would be identical as to 

 minutes and seconds all over the earth. It is 

 probable that the gentle pressure of this con- 

 venience will, after a while, bring about the 

 desirable concurrence, especially as the in- 

 creasing extent and rapidny of travel and com- 

 munication will all the time bring out more 

 forcibly the inconveniences of the present 

 state of affairs, and tend to weaken mere local 

 feeling and prejudice, which, after all, is the 

 main obstacle at present to the universal 

 adoption of the meridian proposed. 



The recommendation that astronomers 

 should come into agreement with other folks, 

 and begin their da} 7 at midnight instead of 

 the following noon, as at present, seems espe- 

 cially likely to fail. The Greenwich observa- 

 tory, indeed, adopted the new plan on Jan. 1 ; 

 but, so far as we know, no other important 

 astronomical establishment has yet done so. 

 Commodore Franklin, of the U. S. naval ob- 

 servatory, proposed to follow the example of 

 Greenwich, and issued an order to that effect ; 

 but it excited so much opposition from cer- 

 tain eminent and influential astronomers, that 

 the order was suspended before the time came 

 for it to go into operation. 



The objections of Professor Newcomb, who 

 has formulated more fully and forcibly than 

 any one else the reasons why the change 

 should not be made, relate not so much to the 

 fact that astronomers would find it inconven- 

 ient to change the date of their observations 

 at midnight, as to the confusion that would be 

 likely to result in the combination and compar- 

 ison of observations taken before the introduc- 



