A. A, Julien on Sponge-Spicules.. . 8st 
Variation. Mean. oe. 
Pe 3 ee s$o — + inch 4 inch 40 
Diameter at middle, - - - | ggsg—zdyinch| 74 inch 58 
“ “end, - = = = bodgo-gabg inch|go'sa inch 15 
Ratio of middle diam. to length, =: - +25 1o5 
Ratio of middle to end diameter, 3. - 4 13 
Diameter of central tube,- - | .gdgq—-rolg inch g7eq inch 45 
Ratio of bore to diameter, - zo -# $ 45 
with acidulated and with pure water, from the intermixed impu- 
rities, particles of sand, etc., and on analysis yielded the follow- 
lng results: 
Water, - - - - - 7-902 
Silica, . : é ; . 89°84 
Alumina, oe - - . 29 
Protoxyd of iron, - - - - "09 
Lime, 4 © se e - ze 
Magnesia, - - - - - 2 
Potassa, - - - - - 63 
99°63 
2 ter pearly. Powder white. ‘Transparent. Elastic. Easily 
tubes. In a closed tube the spicules whiten, curl, and yield 
water. Unaffected by the acids, hot or cold, but readily soluble 
ina solution of caustic pote : sa be shy 
. Acicular, tubular, and gently-curving spicu “Only. vat 
gradually from the middle toward either extremity, 
Am. Jour. Scr.—Szconp Serres, Vou. XL, No. 120.—Nov., 1865. 
