MUSEUM OF COMPARATIVE ZOOLOGY 



33 



from Sept. 8, 1909, to July 29, 1910 (Concluded). 



TION or 



Distance 



Range 





1st Pre- 

 liminaries 



All Pre- 

 liminaries 



1+A = | 3A = 

 V2-V1 ( W1-V1 



Remarks 



h. m. s. 



m. s. 



Miles 



Miles 



mm. 



2.0 

 23.0 



Periods of 6 sec. 





12 29 





2600 



1.5 

 0.7 

 0.5 



9.0 



E. W. ticker out of order. 



Not reported from other Stations 



N. & W. 

 Began 3-14 at Ottawa. 



5 36 



13 50 



2500 



2860 



050 







14 58 

 49 34 





3100 

 10250 



0.2 

 1.0 



Shocks reported at Rock Springs, Wyo., 



last night and this a. m. 

 Indistinct records. 



by Laska's rules I and II. By Rule I, the distance in mega- 

 meters is equal to the difference in minutes between the times of 

 arrival of the 1st and 2nd preliminaries, minus 1; by Rule II, 

 the difference between the times of arrival of the 1st preliminary 

 and the main or long waves in minutes is three times the distance 

 in megameters. For ascertaining the distance by the chart, 

 where the 1st and 2nd preliminaries are known, find their differ- 

 ence in minutes and parts of a minute (seconds or tenths) ; enter 

 the table at the bottom on the line of minutes, and above in the 

 line of megometers or miles as desired will be found the distance 

 by Laska's Rule I. If the distance in degrees of arc is desired, 

 follow the vertical line up to the line of Degrees of arc. To 

 obtain the distance according to Laska's Rule I with Benndorf's 

 Corrections, enter the table as before, and follow the oblique 

 lines which will give the best reading. To obtain the distance 

 by Rule II, enter the table above at the line marked Laska's 

 Rule II; follow down to the lines of miles or kilometers as before. 



