338 C. U. Shepard, S1., on the Phosphatic Formation. 
tenth of a milligram only, and shows that even by a pres- 
sure of 0:184 meter the washing is as complete by the single 
addition of 26 cub. centims. of water. The duration of the 
tering process in the former experiments ranged from 12 to 
14 minutes under a difference of pressure amounting to from 
0°53 to 0572 meter ; in the last experiment it required 25 min- 
utes under a pressure of 0-184 meter, or about double the 
length of time. The time needed to analyze potassium chro- 
mate in the former case was reduced from 14 hours to 32 min- 
utes ; by the latter method the reduction would be from 14 
ours to 44 minutes. 
The employment of the second method is particularly to be 
recommended to beginners in qualitative analysis, The experi- 
menter needs only a single funnel, he is obliged to work care- 
fully and cleanly, and the great saving of time and work amply 
compensates for the little trouble needed to reverse from time 
cc Lomenetr By its aid it is possible to calibrate a thermometer 
Ce ee 
I purpose returning to these applications of the instrument 
in a future communication. 
oo 
Ann. XXIX.—Note upon the origin of the Phosphatic Forma- 
: tion; by C. U. Sueparp, Sr. 
yeral 
explanations suggest themselves. Among these the best answer 
ne for a long period, r rotruded many feet above the prese™ 
8; giving rise to a luxuriant soil (analogous to that OW 
ich was then depressed beneath the sea, where it unde — 
