A file ending in .001 is part of a "split" 7-Zip archive. You cannot open it in isolation; you must have all sequential parts (e.g., .001 , .002 , etc.) in the same folder to reconstruct the original data.

The original Latin text or the English translation (often by Andrew Motte) regarding the laws of motion and universal gravitation.

Complete copies are available via the Internet Archive and Project Gutenberg .

Select "Extract Here" or "Extract to [Folder Name]". The software will automatically detect and join the subsequent parts.

Depending on the source of your download, the archive likely contains one of the following: