732 Dr, G. A. Shakespear: Experiments on the 



(2) Relation between Air Resistance and Diameter of 

 Spheres. — This was determined carefully by the method of 

 simultaneous fall for a limiting velocity of 1030 cm. /sec. 

 with the following result, when D = diameter in cm., W= 

 weight (in air) of the sphere : — 



D. 



W. 



& 



cm. 



gms. wt. 



gms./cm. 3 



752 



1373 



2-85x10-4 



6-27 



9-128 



2-73 „ 



4-97 



5-714 



2-72 „ 



3-70 



3030 



2-60 „ 



2-01 



'887 



2-58 „j 



(Curve B in figure.) 



(3) Many experiments were made with more heavily 

 loaded spheres and consequently higher velocities, but as in 

 these cases the limiting velocities were not attained, the 

 results are only given in terms of the weight (in air) of 

 spheres which fall a distance of 3800 cm. in equal times. 



W x , W 2 , &c, represent the weights of the spheres, and 

 D 1? D 2 , &c. their respective diameters. The values of W in 

 any horizontal row represent the weights of the spheres 

 which take the same time to fall the distance of 3800 cm. 



The ratio — is given in each case, and it will be seen that 



for a given time of fall, the weight is nearly proportional to 

 the square of the diameter of the sphere. 



B^l'58; D 2 =6-29; D 3 = 5'00 ; D 4 =3'71. 











W, 



W 9 



w 3 



W 4 



w x . 



W 2 . 



W 3 . 



W 4 . 



Di 2 ' 



D 2 2 * 



D 4 * 



11-180 



7770 



4-805 



2-555 



•194 



•196 



•200 



•179 



13-55 



9-432 



5-778 



3-325 



•235 



•238 



•235 



•232 



15-95 



11-19 



6848 



3-863 



•277 



•282 



•274 



•270 



18-45 



12-82 



7'972 



4-516 



•320 



•323 



•319 



•316 



21-39 



15-20 



9-390 



5-151 



•371 



•383 



•376 



•360 



24-90 



17-37 



10-45 



5-993 



•431 



•437 



•418 



•419 



28-48 



19-55 



11-85 



6-741 



•494 



•493 



•474 



•471 



34-00 



23-87 



14-56 



8-304 



•590 



•602 



•582 



•580 



40-54 



28-22 



1709 



9-810 



•704 



•711 



•684 



•685 



47-06 



33-51 



20-03 



11-46 



•816 



•844 



•803 



•802 



