3 26 Journal of Agricultural Research v©i. xxm, no. s 
Of the seeds used in this field investigation, those of beans, beet, 
muskmelon, onion, parsley, peas, squash, tomato, and watermelon were 
included also in the chamber tests with different alternations of tempera¬ 
ture previously discussed. It will be remembered that all of these except 
tomato germinated with equal completeness in all of the chamber tests 
but that the rapidity of germination varied according to the character 
of the alternation. 
The bean, beet, onion, parsley, pea, and tomato seeds produced the 
first seedlings in the smallest number of days during the moderately warm 
weather of May or during the latter half of June, when the temperature 
was similar to that in May. Muskmelon, squash, and watermelon seeds 
produced the first seedlings in the smallest number of days during the 
very warm weather of the first half of June. 
It should be remembered in this connection that the production of 
seedlings in the field involves not only the germination of the seeds 
but the piercing of the overlying soil by the young seedlings—a process 
which reflects the vigor of growth of the seedlings and may be retarded 
by excessively high temperatures, even when these same temperatures 
hasten germination as with Johnson grass seed (see p. 307). Since, 
however, the seedlings of the kinds of seeds here considered appeared 
normal and vigorous in all the alternations and also in the field, and 
since the chamber conditions giving most rapid germination gave also 
