18 



nu: MECHANICS OF THE EARTH'S ATMOSPHERE. 



The following observations were made with two square disks of 6 



inches on each side,* 6 indicates the weight placed in each scale pan. 

 and this changes to Q when we subtract the weight required to over- 

 come the resistance of the arms for equal velocities. The second col- 

 umn contains as before the times during which the index sinks by 1 

 inch, as found from the two measurements respectively. 



Adopting the expression. 



Q = : 



-'- 



I find as most probable values 



- 



- 124.24 



From this the values of G given in the column marked A are deduced 

 for the respective times. The errors of these, as contained in the fol- 

 lowing column, vary so much in sign that we can consider them as 

 accidental ami there is no reason in introduce still another term in the 

 above expression. In this connection it must still be mentioned that 

 when in the computation of theeariierobservations I have assumed the 

 coefficient ;> equal to sero, a satisfactory agreement of the resistances 

 appears for larger disks as soon as 1 set the resistance proportional to 

 the square of the velocity. This is explained by the fact that the value 

 of the term " is very small in comparison with the stronger resistances 

 which the disks experience. 



[*In»lltl jit is 1 rsl . s for the 



• - a ofth< - - - - - .i been made with 



tlu a - - terminal combined t :. for arms 



P ll> • ;e due to the arms luis been 



puted. - _ Mne the fiietkm pins the iwBBtauioe of 



tbe ~ a tnm ~ _r required to o- : ion plus resistai r 



of the air to the motiou of the disks : 3 is the weight required to overcome the 



,-ht required to overcome the resistance! to the disks. C. >.] 



