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pits) 
260 BOTANICAL GAZETTE [APRIL 
The best beans I have found for the purpose are horse beans. 
which are little liable to mold, while chopped sphagnum moss is 
the best medium I have found for growing seeds in almost any 
physiological experiments. The entire apparatus costs less than 
ten dollars. 
3. A self-recording auxanometer. 
The study of growth in the higher plants, and of howit is 
influenced by external conditions of light, temperature, moisture, 
etc., is always an important topic in an elementary course, and 
for it a self-recording auxanometer is needed. Many forms have 
been devised, but none has come into general use, except the 
well-known Albrecht form, which costs over $100. I have 
made a fair instrument, shown in fig. 3, constructed as follows: 
Take a dollar clock and remove hands, face and all surplus 
wheels, which will leave a round steel spindle three-fourths of 
an inch long projecting above the works. Have turned ne 
lathe a hardwood cylinder, twelve inches long and an inch i 
diameter, with a hole turned in one end truly in, the contels ' 
little smaller than the steel spindle of the clock. The a 
is then forced down on the spindle and stands vertically a 
firmly, revolving once an hour. Have turned also ons lathe 3 
double wheel as shown in the figure, the larger as thin, # ee 
sible, six inches in diameter, grooved on the edge, and i 
smaller an inch in diameter, the whole carefully and lightly va" 
nished with shellac to prevent warping. Through the ge 
this double wheel a small smooth hole is turned on hee 
and by this hole the wheel turns on a clean a - ar 
soldered horizontally to a firm support. The wheel will ye 
on the needle with very slight friction. A fine silk pea © : 
fully and finely waxed (to prevent hygroscopic annie 
water) is attached in the usual way to the tip of 
growing part (such as a flower stalk of hyacinth ce drop 
times around the small wheel, and fastened by 4 
glue. A similar thread is run in reverse direction * n against 
wheel twice and fastened. The other end carries eT . 
psa Hp ey ae etn 
