The output nf stone from quarries is greatly diminished (from 12,500,000 tons, worth 1/21,920,000, in 1890, to 8,000,000 tons, worth 1/2f 400,000, in 1899), a circumstance probably attributable to the slackening of building enterprise in many cities, and to the decrease in the demand for stone for railway, maritime and river embankment works.
2; in addition, cn, nerve cord; in, intestine; nf, parts of nephridium; on, external opening of nephridium; ov, ova; 1, testis.
1 with the addition of NF, neural fossa protecting the aggregated ganglia of the central nervous system; PVP, left posterior ventral process; PMP, posterior median process.
Nf, Nerve fibres.
Friction of Teeth.Let N be the normal pressure exerted between a pair of teeth of a pair of wheels; s the total distance through which they slide upon each other; n the number Of pairs of teeth which pass the plane of axis in a unit of time; then nf NI (63)
Tahir ultimately (820) i~eceived the ctntrnrnnrahin nf Vhnr~can wIlprc, lip ~, s,~,,l,-l;~ sct~hrich;na a practically independent Moslem dynasty (the Tahirids)i which ruled until about 873 in nominal obedience to Bagdad.