METEOROLOGY. 



Table I. — Vettiv's observations of clouds at Berlin — Continued. 



529 



The study of the cirrus daring all three years gave the same result 

 as for the first two, viz, that the upper cirri move with one-third less 

 velocity than the lower. It follows that wheu various cirri are seen 

 together on any day, aud are moving with the same velocity, they be- 

 long to the same layer, either upper (23,000 feet) or lower (12,800 feet). 



The variations with season in the altitude and velocity of motion of 

 these five classes of clouds are given in the following table, based on two 

 years' observations, where the projected velocities of the five strata are 

 referred to that of the upper cirrus (57 feet per second) as unity. The 

 absolute altitudes are given in hundreds of feet and the relative alti- 

 tudes in terms of that of the lower clouds : 



H. Mis. 09 34 



