302 



REPORT — 1851. 



Table No. 6. 

 Being the Results of all the preceding experiments reduced to one uni- 

 form range or distance of 5280 feet, or one statute mile. 



In the preceding Table the value of each transit time is proportionate to the 

 actual range ; therefore in taking the mean each individual range is to be 

 multiplied into its time per mile, and the sum divided by the sum of the 

 ranges for the true mean. 



Table No. 7- 



3Ieans of Means. 



Mean of 1 and 2 = 4-2087 



Mean of 2 and 3 =3-8555 



Mean of 1 and 3 = 3-7379 



Mean of 1, 2 and 3 = 3-9340 



Adopting the experiments A, C, D, E, F, G on the more shattered gra- 

 nite as a separate set, their gross mean is 4"-3263 of time of transit for one 

 mile. 



And also adopting the experiments H, I, K on the more solid mass of 

 granite as a separate set, their gross transit time is 3"-3847 of time for 

 one mile. 



* This experiment is doubtful 



