Almost 90 years after Einstein postulated his general theory of relativity -- our current theory of gravity -- scientists have finally finished collecting the data that will put this theory to an ...

Even before von Lilienthal's sug- gestion, Etrich and Weis had patented a similar idea, but had abandoned it during construction. $ While no experiments were made, more mature consideration led to the ...

THIS is an admirable little book suitable from every point of view as a present for a boy with a mechanical turn of mind. As the extended title indicates, the properties of the gyroscope are ...