10 The Development of the Male Prothallium [January, 
somewhat flexed from the level until it runs out on the southern 
edge of the basin. At the summit of the second dip another 
slope has been opened, and between these two slopes stands the 
giant coal-breaker, supplied with coal by the action of immense 
engines which draw, by means of wire rope, the loaded cars to 
its lofty height. The coal is drawn, in the second slope, up an 
incline of 424 feet by means of a wire rope 4300 feet in length, 
and nearly two inches indiameter. About 600 cars are daily 
hoisted by this rope, and the cars are drawn 174 feet up the in- 
cline within the breaker alone. This anticlinal, flexure, or saddle, 
brings into near proximity to the breaker a vertical mass of coal 
twelve feet in thickness and nearly 200 feet in height, and extend- 
ing eastward and westward up and down the valley, to thin out 
as the conglomerate rises, basin-like, to its outcropping edge. 
During 1880 there were three breakers in the basin, employing 
389 men inside and 215 outside the mines. To open the mine 
-and break up the coal from its beds. 1514 kegs of powder, weigh- 
ing twenty-five pounds each, were used, and the product of 
330,444 tons of coal of 2240 lbs. each were sent to market. This 
valley and its plant for mining is the property of one family, and 
has proved, under their enterprise and energy, a princely domain. 
A’ 
MS 
THE DEVELOPMENT OF THE MALE PROTHALLIUM 
OF THE FIELD HORSETAIL. 
BY PROFESSOR DOUGLASS H. CAMPBELL. 
lepers the vascular cryptogams, perhaps none can be more 
satisfactorily studied than Eguisetum arvense, both as regards 
the structure of the mature plant and that of the prothallium; the 
plant being a common one, and readily obtained for study. The 
growth of the fertile plant is very rapid, so that the cells are 
large and distinct, and being comparatively free from the silicious 
deposit so noticeable in most of the other species, it is much less 
difficult toexamine. Finally, and what is of chief interest here, 
the spores germinate very readily if sown immediately after ma- 
turing, and offer a most interesting example, in their development, 
of the growth and division of cells. Within a few weeks of sow- 
ing, the antheridia are. produced abundantly, containing anthero- 
zoids of extraordinary size, much larger than those of the mosses 
-and ferns. 
