LESSORS 0^" POTATOES FOE EURAL SCHOOLS. 23 
well-tested methods for preparing potatoes for the table should be 
given and demonstrated. 
Practical exercises. — In studying the composition of the potato, the 
pupils may make the tests themselves. (Caution: Be careful in 
handling the nitric acid. ) Demonstrations in the methods of cooking- 
potatoes may be made in the classroom. Recipes may be given out 
and the actual preparation may be done at home. If school lunches 
are served, the potato may form one of the foods served. Potatoes 
as a substitute for flour in various dishes may be demonstrated. The 
demonstrations at school should be followed up with the preparation 
of the same recipes at the home of the student. 
Correlations. — Construct charts for the classroom showing the 
structure and the composition of the potato with relative amounts of 
each constituent. 
Neat copies of recipes, reports on cooking processes, and a write-up 
of the study of the composition of the potato will give practice work 
in language, while a booklet on the uses of the potato well written, 
carefully prepared, and illustrated, if possible, will give correlation 
both in language and drawing. 
Problems showing comparative cost of potatoes as a source of starch 
food with other starchy foods, and like comparisons as to supply of 
minerals, will afford practice work in arithmetic. 
SUPPLEMENT. 
Formula for Treatment of Seed Potatoes. 
1. One pound 40 per cent formaldehyde to 30 gallons of water. Soak tubers 
for 2 hours. May be used over and over again for at least 10 times. 
1 2. Four ounces dry corrosive sublimate to 30 gallons of water. Dissolve the 
powder first in a quart of warm water and then add it to the other. This solu- 
tion should not come in contact with metal. Should not be used more than three 
times unless renewed. Soak potatoes for at least 1^ hours. Handle with great 
care, for this solution is very poisonous. 
BORDEAUX MIXTURE. 
Five pounds copper sulphate (blue vitriol). 
Five pounds stone lime. 
Fifty gallons of water. 
Dissolve the copper sulphate in water. 
Slake the lime with water. Then mix in a barrel containing 50 gallons of 
water. If desired, a 3.3 : 50 solution may be made, but the above is better. 
If used to any extent, slake solutions of both the copper sulphate and lime should 
be prepared and then added to the water when ready to use. 
If desired to kill potato beetles or other insects, add to the Bordeaux mixture 
from 3 to 5 pounds of arsenate of lead or 1 pound of Paris green, and add 2 
pounds of quicklime to prevent burning. One pound of Paris green to the acre 
either in water or Bordeaux mixture is ordinarily recommended. Arsenate of 
lead has the advantage of adhering to the vines and is only slightly washed off 
by the rains. 
