This series includes various scientific articles written by faculty members at the University of Wisconsin. Topics covered range from botany and zoology to astronomy and geology. The articles are written in a way that is accessible to both students and non-experts. Whether you are a science enthusiast or just looking to expand your knowledge, you will find something of interest in this series. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.