68 [ ASSEMBLY 
Merch. tubers. Unmerch. tubers. 
Potatoes covered with straw.... 84 1-4 lbs. 18 1-2 lbs. 
Potatoes covered with sand..... 184 lbs. 3 1-3 lbs. 
Potatoes on ridges, and the inter- 
vals aMUIGNEGs a a thi vara 92 1-3 lbs. 22 1-2 lbs. 
Ordinary level culture........ . . A 1-2 Ibs: 14 lbs. 
Ordinary ridge culture......... 83 1-2 Ibs. 7 1-2 lbs. 
We thus see a confirmation, so far as one trial is concerned, of the 
hypothesis. In the straw, coolness and dampness for root and tuber 
in the spring when dryness of the upper portion seems neither essential 
nor advantageous, for then vegetation is becoming established ; in the 
summer, dryness without heat for the upper portion. In the sand, 
heat and dryness for the tubers, moisture and coolness for the roots. 
In the ridging and mulched intervals, a moderate amount of dryness 
(would have been greater in an ordinary season), and moisture and 
coolness for the roots. In the ordinary ridge culture on this soil, a 
greater approach to the condition which the sand supplied than in the 
ordinary level culture. 
We may be pardoned, in view of the importance of these thoughts, 
if we depart from our usual plan, and call attention to a few practical 
remarks. 
The question of level or hill culture may, after all, be but a ques- 
tion as to how to secure certain conditions. We may understand, with 
the help of these experiments given, that in clay soil ridging may 
secure in ordinary seasons those conditions which on loamy or sandy 
soil are secured better by level culture. In view of the agency of the 
seed used, and the effect of a greater or less fertility, or better or worse 
physical character of the soil as influencing, we must wait for further 
experiments for the verification of the results which one trial renders 
probable. Favorable condition of soil may sometimes offset improved 
methods of planting, and in this view the accidental use by us of land 
too poor to raise a good crop under ordinary circumstances, may pos- 
- sess its advantages. ‘This land which could raise only a calculated 
crop per acre under ordinary level culture of 86-2 bushels, or under 
ridge culture of 151-5 bushels, yet, under theoretical circumstances, 
yielded upon the same soil at the rate of 334 bushels per acre. 
3. One plant was divided into three parts in order to observe the 
effect of cultivation. ‘Three rows were kept weeded by hand; three 
rows were hoed without hilling; two rows forked over deeply between 
rows. ‘The yields were as below: | 
Merch. tubers. Small tubers’ 
Three rows (75 plants) not cultivated ...... 48 lbs. 16 1-2 lbs. 
Three rows (75 plants) ordinarily cultivated. 52 3-4 lbs. 20 1-4 lbs. 
Two rows severely cultivated..... ....... 14 1-2 lbs. 8 lbs. 
In every case a potato forms its tubers above its roots, and these 
tubers occupy the upper layer of the soil, while the roots pass down- 
ward and outward. Upon August 5, we washed out the roots of a 
potato plant growing upon a ridge, and the half potato used as seed 
put six inches below the surface. A trench was first cut across the 
ridge and carried to a sufficient depth. ‘Then a force-pump was 
