Welding welding was invented in 1893, and around that time another process, oxyfuel welding, became well established. Acetylene was discovered in 1836 by Edmund Davy, but its use was not practical in welding until about 1900, when a suitable torch was developed. At first, oxyfuel welding was one of the more popular welding methods due to its portability and relatively low cost. As the 20th century progressed, however, it fell out of favor for industrial applications. It was largely replaced with arc welding, as advances in metal coverings (known as flux) were made. Flux covering the electrode primarily shields the base
Discovered attack 2.hxg6++. The result is a "double discovered check": One check is given by the rook, discovered by the capturing pawn's move; the other by the bishop, discovered by the captured pawn's removal. Such a check is extremely rare in practical play, but is sometimes found in problems. The diagram illustrates a trap in the Advance Variation of the French Defence, based on a discovered attack. If, after 1.e4 e6 2.d4 d5 3.e5 c5 4.c3 Nc6 5.Nf3 Qb6 6.Bd3 cxd4 7.cxd4, Black mistakenly attempts to win White's d4-pawn with 7...Nxd4 8.Nxd4 Qxd4 (diagram), White can play 9.Bb5+, a discovered attack (White's