LESSOITS 0'^ POTATOES FOR RURAL, 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. Eecipes 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 v/rite-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 foe 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. 



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 renev\-ed. Soak potatoes for at least IJ 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. 



