were four divisions in the cooper's craft. The "dry" or "slack" cooper made containers that would be used to ship dry goods such as cereals, nails, tobacco, fruits, and vegetables. The "dry-tight" cooper made casks designed to keep dry goods in and moisture out. Gunpowder and flour casks are examples of a dry-tight cooper's work. The "white" cooper made straight-staved containers like washtubs, buckets, and butter churns, which would hold water and other liquids but did not allow shipping of the liquids. Usually there was no bending of wood involved in white cooperage. The "wet" or "tight" cooper made casks for long-term storage and transportation of liquids that could even be under pressure, as with beer. The "general" cooper worked on ships, on the docks, in breweries, wineries and distilleries, and in warehouses, and was responsible for cargo while in storage or transit. Ships, in the age of sail, provided much work for coopers. They made water and provision casks, the contents of which sustained crew and passengers on long voyages. They also made barrels to contain high-value commodities, such as wine and sugar. The proper stowage of casks on ships about to sail was an important stevedoring skill. Casks of various sizes were used to accommodate the sloping walls of the hull and make maximum use of limited space. Casks also had to be tightly packed, to ensure they did not move during the voyage and endanger the ship, crew and cask contents. Whaling ships in particular, featuring long voyages and large crews, needed many casks – for salted meat, other provisions and water – and to store the whale oil. Sperm whale oil was a particularly difficult substance to contain, due to its highly viscous nature, and oil coopers were perhaps the most skilled tradesmen in pre-industrial cooperage. Whaling ships usually carried a cooper on board, to assemble shooks (disassembled barrels) and maintain casks. Coopers in Britain started to organise as early as 1298. The Worshipful Company of Coopers is one of the oldest Livery Companies in London. It still survives today although it is now largely a charitable organisation. Many coopers worked for breweries. They made the large wooden vats in which beer was brewed. They also made the wooden kegs in which the beer was shipped to liquor retailers. Beer kegs had to be particularly strong in order to contain the pressure of the fermenting liquid,