BULLETIN OF THE BUSSEY INSTITUTION. 11 
hold use. This sand consists of very fine and light 
particles, which have manifestly come to rest from the 
sea-water in some sheltered bay or cove. . . 2.384 0.051 
Coarse dune sand of light reddish-brown color froth a 
hill at Provincetown, Mass., collected i Capt. Nath. 
E. Atwood of thattown. . . 0.613 0.050 
Pit sand from beneath field next adj joining the Plain-field 
of the Bussey Institution . . 0.891 0.035 
Pure white. Berkshire County sand Bhininedst in 1872 te om 
glass-houses in vicinity of Boston. . . . .. . . 0.448 
Ditto, — Another sample obtained in 1874 . . . . . 0.630 0.021 
The foregoing results consist perfectly with those observed in other 
countries, as may be seen by consulting the extensive collection of 
rock analyses published some years since by J. Roth, under the title 
“Die Gesteins-Analysen,’ Berlin, 1861. Stoeckhardt also, in his 
“Chemische Ackersmann,” 1862, 8. 112, has drawn up a synopsis 
from which it appears that the amounts of potash contained in ordi- 
nary rocks are somewhat as follows: In pure potash feldspar, there 
is found from 10 to 16% of potash; in potassic mica and in several 
kinds of volcanic rocks 8 to 10%; in certain Saxon feldspars and 
green sands, phonolite from Bohemia, pumice and trachyte from the 
Rhine 7 to 8%; in granulite and porphyry from Saxony and Aus- 
tria, in some mica slates, roofing slates, and phonolites 6 to 1%. In 
some kinds of granites, syenites, gneisses, and mica slates 5 to 6% ; in 
other kinds of the rocks last named, and in some clay slates, porphyries, 
and traps 4 to 54%; in still other kinds of the rocks just named, 3 to 
4% ; in certain Swiss granites, in gneiss from Sweden, in mica slate 
and clay slate from Saxony, and in various volcanic rocks 2 to 3% ; 
in various clay slates and basalts 1 to2%. Hornblende slate, serpen- 
tine, &c., are often still poorer than this in potash and so are many 
lime stones. 
Boricky, in his treatise “Ueber die Verbreitung des Kali und 
Phosphorsiiure in den Gesteinen Béhmen’s,” Prag, 1872, gives the 
maximum and minimum amounts of potash that have been found in 
granites as 2 and 7% ; in gneisses the amount of potash ranges from 
2 to 5%, in granulites and syenites from 1 to 7%, in porphyritic 
rocks from 1.3 to 7.9%, in mica slates from 1 to 4%, in clay slates 
from 1 to 6% and in basalts from 0.5 to 4%. He found that phos- 
phorice acid ranged from 0.1 to 0.5% or more, in the fine grained 
granites, and that there was rather more (about 0.5%) in gneissoid 
