You are currently logged out. Please sign in to download the issue PDF. In the Mexican valley of Tehuacn bands of hunters became urban craftsmen In the course of ...

You are currently logged out. Please sign in to download the issue PDF. Onion Portage in Alaska is an unusual Arctic archaeological site. It provides a record of ...

You are currently logged out. Please sign in to download the issue PDF. In 1957 it was found that the cell defends itself against viruses with a protein called ...

You are currently logged out. Please sign in to download the issue PDF. Computers today add at a rate of 10 million calculations per second and will soon add even ...

You are currently logged out. Please sign in to download the issue PDF. The life of an oil well can be extended by techniques that push oil out of the rock after the ...

You are currently logged out. Please sign in to download the issue PDF. Three inscribed tablets found in Romania may be 1,000 years older than the oldest examples of ...

You are currently logged out. Please sign in to download the issue PDF. This broad, 8,000-mile-long bulge in the crust of the earth differs in many ways from the rest ...

You are currently logged out. Please sign in to download the issue PDF. Until recently it seemed that the islands of the Caribbean were uninhabited up to about the ...

You are currently logged out. Please sign in to download the issue PDF. An issue devoted to science in its strict sense: the interrogation of nature. This ...

You are currently logged out. Please sign in to download the issue PDF. The atmosphere of the sun may extend beyond the orbit of the earth before its density falls to ...

You are currently logged out. Please sign in to download the issue PDF. An issue on cities: how they arose, how they are evolving in various circumstances, how they ...

You are currently logged out. Please sign in to download the issue PDF. For 2,000 years geometry meant Euclidean geometry. Then it was found not only that other ...