Large seeds demand much less care as to depth of covering, as a rule. One-fourth or one-half inch is a good depth for most coarse seeds in-doors. If one wishes to gauge the depth accurately, the drills may be made by a planting stick, like that shown in Fig. 8. Its flange is made of the required thickness, and it is pressed into the soil until the cap strikes the surface. This is a useful implement in seed testing. Another device for regulating the depth of sowing, particularly in seed testing, is the Tracy planter, shown in Fig. 9. It consists of two strips of heavy tin plate about three inches wide, hung upon two wire pivots or hinges some two inches long. At their upper edges and equidistant from either end, the plates are joined by a firm spiral spring, which serves to throw the upper edges apart, and to cause the lower edges to join. This trough is now filled with the required number of seeds, and is then inserted into the earth to a given depth, when the fingers push inward on the spring and the trough opens and delivers the seeds. [Illustration: Fig. 8. Planting Stick.] =Miscellaneous Matters.=--The influence which light exerts upon germination is not definitely understood. It is known, however, that seeds will often germinate in full sunlight, if the proper conditions of moisture and temperature can be maintained. Seeds sown upon a moist surface and covered with a glass present an interesting study. But it is well known, on the other hand, that some seeds will not germinate, or will at least appear unevenly, if subjected to sunlight. At least some of the delphiniums, papavers and adonises germinate very imperfectly, if at all, in direct light. It is always advisable to keep germinating seeds in shade or partial darkness, especially as there is nothing to be gained by exposing them. Of course the soil itself is sufficient protection if the seeds are covered. [Illustration: Fig. 9. Tracy Planter.] It is a common statement that seeds can never revive if allowed to become thoroughly dry after they have begun to sprout. This is an error. Wheat, oats, buckwheat, maize, pea, onion, radish and other seeds have been experimented upon in this direction, and they are found to re-germinate readily, even if allowed to become thoroughly dry and brittle after sprouting is well progressed. They will even re-germinate several times. Wheat, peas and other seeds have been carried through so many as seven germinations after the radicle had grown a half inch or more and the seeds had been sufficiently dried in each trial to render them fit for grinding.