in the Velocity of Propagation of Light in Water. 359 



Water. 



Tempera- 

 ture, C. 



volume, 



v° = l. 



A. 



BIO 12 . 



M = 



(A 2 -l>. 



Bw 3 10 12 T 



(A- 1)». 



o 







1-000000 



1-32432 



3250 



0-75382 



3250 



0-32432 



1 



0-999947 



1-32432 



3250 



0-75376 



3250 



0-32430 



2 



0-999908 



1-32431 



3250 



0-75372 



3249 



0-32428 



3 



0-999885 



1-32430 



3248 



075368 



3248 



0-32426 



4 



0-999877 



1-32429 



3247 



0-75365 



3247 



0-32425 



5 



0-999883 



1-32428 



3246 



0-75362 



3246 



0-32424 



6 



0-999903 



1-32426 



3245 



0-75360 



3245 



0-32423 



7 



0-999938 



1-32424 



3245 



0-75357 



3245 



0-32422 



8 



0-999986 



1-32421 



3243 



0-75352 



3243 



0-32420 



10 



1-00015 



1-3241 



3240 



0-7534 



3240 



0-32415 



20 



100169 



1-3236 



3213 



0-7532 



3224 



0-32415 



30 



1-00423 



1-3228 



3171 



0-7529 



3198 



0-32415 



40 



100761 



1-3216 



3122 



0-7522 



3177 



0-32405 



50 



101185 



1-3201 



3076 



0-7514 



3149 



0-32390 



60 



1-01684 



1-3183 



3044 



0-7503 



3148 



0-3237 



70 



102253 



1-3162 



3043 



07489 



3182 



0-3233 



80 



1-02882 



1-3140 



3088 



0-7475 



3194 



0-3230 



90 



1-03568 



1-3115 



3202 



0-7457 



3435 



0-3226 



100 



104303 



1-3089 



3405 



0-7439 



3705 



0-3222 



From the above numbers we see that the magnitudes M and N 

 given by Schrauf are by no means constants, but vary continually 

 with the temperature. If all the differences did not fall on the 

 same side, and if the increase and diminution were not so per- 

 fectly regular as they actually are, we might still be in doubt. 



_Aj2 ]_ 



But since the sign of the differences in the column never 



o v 



alters within the limits of observation, the above assertion can 

 scarcely be other than true. 



At the same time it is remarked that the maximum density is 



not able to overcome the diminution either of ~— = — , or of 



A— 1 

 d 



d 



both magnitudes continually increase with increasing 



A-l 



temperature. Also the " specific refractive power n — -= — , which, 



a 



according to Gladstone and Dale, should be constant, diminishes 

 so regularly with the temperature that there can be no possibi- 

 lity of its constancy. The numbers reckoned for this value 

 from their own experiments by these physicists themselves, show 

 the distinct and well-marked tendency of the value to diminish 

 at higher temperatures. 



2B2 



