Page:Popular Science Monthly Volume 46.djvu/659

Rh, at Waverly, Mass. "Here is one which is cheap, but limited in its possibilities. It can only feed so many lights, or will only give me so much horse power. Here is one larger, perhaps, but not noticeably so, which is warranted to support ten times the circuit, and to develop ten times the gauge of physical motive energy. I examine them closely, and I find the difference of the two to consist in the complexity of their coils of wire. The lesser power dynamo, with fewer volts, has coarser coils and fewer of them; whereas the more powerful developer of energy consists

of endless and delicate windings and layers of wire." The difference between the normal and idiotic brain is entirely one of complexity.

The central nervous system consists practically of ingoing fibers from the various organs of sense, and of nerve cells for receiving and retaining impressions conveyed by these fibers. By some as yet unexplained power of co-ordination these cells