290 



Drs. L. Mond, W. Ramsay, and J. Shields. 



and A x and A 2 are respectively the areas of the curve measured for 

 small lengths x x and x 2 at either end of the range. 



The following gives a comparison of the frequencies of the 

 various degrees of cloudiness, as given by observation, and by the 

 areas of the curve : — 



Degree. 



Observation. 



Calculation. 







751 



803 



1 



179 



142 



2 



107 



72 



3 



69 



60 



4 



46 



51 



5 



9 



50 



6 



21 



55 



7 



71 



60 



8 



194 



85 



9 



117 



153 



10 



2089 



2122 



Considering the rough nature of cloudiness observations, the agree- 

 ment must be considered fairly good, and very probably the smooth 

 results of the theory* are closer to the real facts of the case than the 

 irregular observations. The chief interest of this Note lies, how- 

 ever, in the fact that it shows the capacity of the theory of skew 

 variation already developed to cover novel and unusual types of fre- 

 quency. 



" On the Occlusion of Hydrogen and Oxygen by Palladium." 

 By Ludwig Mond, Ph.D., F.R.S., William Ramsay, Ph.D., 

 LL.D., Sc.D., F.R.S., and John Shields, D.Sc, Ph.D. Re- 

 ceived December 8, — Read December 16, 1897. 



(Abstract.) 



During their investigations on the nature of the occlusion of gases 

 by finely divided metals, and in particular on the occlusion of hydro- 

 gen and oxygen by platinum black, the authors have had occasion to 

 examine the behaviour of palladium to these gases. 



The palladium was employed in three states of aggregation, viz., in 

 the form of (a) black, (b) sponge, and (c) foil. Palladium black, 

 prepared in the same way as platinum black, contains 1*65 per cent, 

 of oxygen, or, taking the density of palladium black as 12'0, 

 138 volumes of oxygen. It differs from platinum black, however, 



* The diagram on which the percentile curves are roughly drawn also indicates 

 the amount of agreement by a histogram. 



