http://book.klll.cc/ebooks/subject/39156.opds 2025-09-20T02:49:42Z Books about Standards of length (sorted by popularity) Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-09-20T02:49:42Z https://book.klll.cc/ebooks/70888.opds On the relative motion of the earth and the luminiferous æther Albert A. Michelson and Edward Williams Morley