The discovery of petroleum in Pennsylvania brought to the fore new illuminating fuels, kerosene and natural gas which were much cheaper than whale oil, so the whaling industry declined rapidly. This happened at the same time steam ships were replacing sailing ships, so it is not surprising that the beautiful sailing vessels which had been the mainstay of whaling were brought home to every little coastal village in New England to rot away, sad memorials to better days. _Modern Whaling_ By the 20th century whaling was again possible because of new uses for whaling products. Chemistry has succeeded in finding new uses for whale oil. Fat derivatives such as soaps, margarines and a few other products owe their abundance and low cost to the whaling industry. Packing house technology has been applied to the butchering of whales so that the entire animal has many uses. Tasty meats are finding their way into the diets of many countries and the tougher, less tasty parts are ground and used to feed cats and dogs. Farms that raise mink and other mammals for the fur trade are heavy buyers of this source of meat to feed their animals. The remaining parts, blood, bones, and meat scraps, are dried and ground into nutritious meals which are used by the poultry and livestock industries as supplementary feeds. Currently each whale produces over $5,000 worth of products. The heart of the processing operation is the pelagic factory ship which is nearly as large as an aircraft carrier. They are supplied by huge tankers which carry off the oil and by refrigerated ships which return the meat to port. In the 20th century the United States has not seriously participated in whaling and has not a single fleet in competition with the other countries which now have billion dollar investments in ships and gear. For the past 70 years, the leader in the whaling industry has been Norway. The industry is very competitive however, and England, Japan, Netherlands, USSR, and Germany have big investments. The Norwegian lead was due principally to Svend Foyn who invented the harpoon with an explosive head. The harpoon was fired by a deck-mounted cannon and it had sufficient range and accuracy to permit killing those whales which heretofore were too fast and wary to be handlanced. The harpoon head had a time delay bomb which insured that the explosion occur deep in the vitals, and that the whale was made fast to a manila line so that it would not be lost. The cannon is mounted in the bow of a small fast ship known as a killer boat. These little ships operate for 1 or 2 days away from the factory ship in search of whales. The gunner who is responsible for firing the cannon is the most important member of the crew and on his experience and skill depend the entire operation. If he misses or fails to kill the whale, it will alarm the other whales and a day or two of searching may have been in vain.