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. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

In the hopes of "preserving these delightful devices for future generations," this collector of slide rules covers everything one could possibly want to know about this crude form of analog computer: from its invention in the 17th century to manufacturers- retailers, 1850-1998, and the Oughtred Society for collectors. Includes a glossary with biographies, patent data, component specs, dating and valuing, care, historical milestones, and illustrations

An investigation of units of measure.

FOREWORD BY GUY KAWASAKI Presentation designer and internationally acclaimed communications expert Garr Reynolds, creator of the most popular Web site on presentation design and delivery on the Net — presentationzen.com — shares his experience in a provocative mix of illumination, inspiration, education, and guidance that will change the way you think about making presentations with PowerPoint or Keynote. Presentation Zen challenges the conventional wisdom of making "slide presentations" in today’s world and encourages you to think differently and more creatively about the preparation, design, and delivery of your presentations. Garr shares lessons and perspectives that draw upon practical advice from the fields of communication and business. Combining solid principles of design with the tenets of Zen simplicity, this book will help you along the path to simpler, more effective presentations.

How do you measure the size of the planet you're standing on? "Circumference" is the story of what happened when one man asked himself that very question. Nicholas Nicastro brings to life one of history's greatest experiments when an ancient Greek named Eratosthenes first accurately determined the distance around the spherical earth. In this fascinating narrative history, Nicastro takes a look at a deceptively simple but stunning achievement made by one man, millennia ago, with only the simplest of materials at his disposal. How was he able to measure the land at a time when distance was more a matter of a shrug and a guess at the time spent on a donkey's back? How could he be so confident in the assumptions that underlay his calculations: that the earth was round and the sun so far away that its rays struck the ground in parallel lines? Was it luck or pure scientific genius? Nicastro brings readers on a trip into a long-vanished world that prefigured modernity in many ways, where neither Eratosthenes' reputation, nor the validity of his method, nor his leadership of the Great Library of Alexandria were enough to convince all his contemporaries about the dimensions of the earth. Eratosthenes' results were debated for centuries until he was ultimately vindicated almost 2000 years later, during the great voyages of exploration. "Circumference" is a compelling scientific detective story that transports readers back to a time when humans had no idea how big their world was--and the fate of a man who dared to measure the incomprehensible.