Block was born at Baldonu, Latvia on April 15, 1847. He studied astronomy at Dorpat and became an assistant there in 1868 (see W. Struve). He changed to Pulkovo Observatory in 1871 (see O. Struve). After two years he went to the Odessa Observatory (Ukraine), where he worked as an astronomer from 1873. He used a 4" comet seeker for visual observations of comets and nebulae. With this instrument he found NGC 1398 on October 18, 1879, published in AN #2287 (1879). But the object was first seen by Winnecke on Dec. 17, 1868 at Karlsruhe (see AN #2293). NGC 1398 is a galaxy in Fornax (in Block's times the area belongs to Eridanus). On the same night Block found the planetary NGC 1360 (first discovered by Lewis Swift 1857 and in Jan. 1868 by Winnecke). He died on May 12, 1912.