In short, observation becomes scientific in nature. Of such observations it may be said that they should follow a rhythm between the extensive and the intensive. Problems become definite, and suggested explanations significant by a certain alternation between a wide and somewhat loose soaking in of relevant facts and a minutely accurate study of a few selected facts. The wider, less exact observation is necessary to give the student a feeling for the reality of the field of inquiry, a sense of its bearings and possibilities, and to store his mind with materials that imagination may transform into suggestions. The intensive study is necessary for limiting the problem, and for securing the conditions of experimental testing. As the latter by itself is too specialized and technical to arouse intellectual growth, the former by itself is too superficial and scattering for control of intellectual development. In the sciences of life, field study, excursions, acquaintance with living things in their natural habitats, may alternate with microscopic and laboratory observation. In the physical sciences, phenomena of light, of heat, of electricity, of moisture, of gravity, in their broad setting in nature--their physiographic setting--should prepare for an exact study of selected facts under conditions of laboratory control. In this way, the student gets the benefit of technical scientific methods of discovery and testing, while he retains his sense of the identity of the laboratory modes of energy with large out-of-door realities, thereby avoiding the impression (that so often accrues) that the facts studied are peculiar to the laboratory. § 3. _Communication of Information_ [Sidenote: Importance of hearsay acquaintance] When all is said and done the field of fact open to any one observer by himself is narrow. Into every one of our beliefs, even those that we have worked out under the conditions of utmost personal, first-hand acquaintance, much has insensibly entered from what we have heard or read of the observations and conclusions of others. In spite of the great extension of direct observation in our schools, the vast bulk of educational subject-matter is derived from other sources--from text-book, lecture, and viva-voce interchange. No educational question is of greater import than how to get the most logical good out of learning through transmission from others. [Sidenote: Logically, this ranks only as evidence or testimony]