1810 - 1904 HAYYIM SELAG SLONINSKI (Bialystok, Poland)
Known as "Hazas". Orthodox mathematician and science writer. His works included Kochva d'Shavit on astronomy, Toldot ha-Shamayim on the calendar and Yesodai Hochmat Hashiur (Founding of the Science of Calculation). He founded Ha'Zefira, a Hebrew newspaper on science. His writings were accepted even by Orthodox Jews.