16 BULLETIN OF THE BUSSEY INSTITUTION. 
“ Almost every kind of sand must be regarded as a mixture of mineral 
fragments of different kinds.” Senft holds* that dune sands usually 
contain from 2 to 25% of mineral fragments other than quartz. On 
carefully examining several samples of diluvial sands, he obtained re- 
sults as follows: In asand from the Mark Brandenburg he found grains 
of hornblende to the extent of 2o,, and grains of orthoclase (potash 
feldspar), to the amount of 17%.f Ina sand from Lusatia he found 
25 0, of orthoclase and some mica also. A sand from the Lunenberg 
heath gave him 4% of basalt grains, and one from Mecklenburg yielded 
10% of orthoclase and 2% of basalt. The fact, long held to be anoma- 
lous, that oaks are found in excellent growth on sand (if moist) in the 
Mark Brandenburg, was satisfactorily explained by Senft’s analysis 
of that sand, as given above.T 
Alexander Miiller { found, like Senft, wide variations in the propor- 
tion of quartz contained in sands. Miiller’s results are specially im- 
portant, moreover, since they were not obtained by any process of 
mere inspection, or of mechanical separation, of the several kinds of 
particles, but by a refined and trustworthy method of chemical analysis 
of his invention, which enables the experimenter to separate every 
thing from the quartz, and to arrive at a very close approximation to 
the true amount of the latter. In a sea-sand, such as an ordinary ob- 
server might have taken for almost pure quartz, and which did actually 
contain a larger proportion (77%) of quartz than any other of the 
samples which he examined, Miiller found that nearly a quarter part 
of the sand consisted of other minerals, of which feldspar was the chief. 
Another very fine-grained sand contained less than 70% of quartz, and 
a sample of Silurian sandstone contained less than 63%. Fine earth 
sifted (through meshes of } millimetre diameter), from land composed 
of glacial deposits, contained only 40% of quartz, and so did a sample 
of diluvial sand. According to Miiller, the amount last named is but 
little larger than what is found in many granites. 
It is noteworthy that, naturally enough, the question of the chemi- 
cal composition of sands has attracted much more attention from for- 
esters who have had to do with the planting of waste tracts than from 
* Op. cit., p. 200. 
t According to Nisbit, “ Transactions of the Highland and Agricultural So- 
ciety of Scotland,” 4th Series, 1876, 8. pp. 288, 290. 
t “ Die landwirthschaftlichen Versuchs-Stationen,” 1868, 10. pp. 157, 158. 
