first recorded in the Jin Dynasty (266–420). During the Tang Dynasty (618–907), it was popular to raise carp in ornamental ponds and watergardens. A natural genetic mutation produced gold (actually yellowish orange) rather than silver coloration. People began to breed the gold variety instead of the silver variety, keeping them in ponds or other bodies of water. Goldfish were introduced into Europe during the 17th century, and into North America in the 19th century. H Hand cannon: The bronze Yuan Dynasty gun from Heilongjiang which dates to about 1288 is a little over 0.3 m (1 ft) in length and weighs 3.6 kg (8 lbs). It has a small touch hole for ignition and an even bore except for the bulbous enlargement around the explosion chamber. It was excavated with a bronze pan, mirror and vase. Hand grenade, explosive: Before explosive grenades, incendiary grenades were used by the Eastern Roman Empire, incorporating Greek fire. Early prototypes to the modern explosive grenade, according to British scientist and sinologist Joseph Needham, appear in the military book, Wujing Zongyao ("Compilation of Military Classics"), by 1044. During the Song Dynasty, weapons known as Zhen Tian Lei were created when Chinese soldiers packed gunpowder into ceramic or metal containers and thrown at the enemy. Further descriptions and illustrations of early Chinese hand grenades are provided in the Huolongjing. Hand gun: An early known depiction of a hand gun is a sculpture from a cave in Sichuan, dating to 1128, that portrays a figure carrying a vase-shaped bombard, firing flames and a cannonball. However, the oldest existent archaeological discovery of a metal barrel handgun is the Heilongjiang hand cannon from the Chinese Heilongjiang excavation, dated to 1288. Handheld firearms first appeared in China where gunpowder was first developed. They were hand cannons (although they were not necessarily fired from the hand, but rather at the end of a handle). By the 14th century, they existed in Europe as well. The first handheld firearms that might better be called "pistols" were made as early as the 15th century, but their creator is unknown. Handscroll: The handscroll originated from ancient Chinese text documents. From the Spring and Autumn period (770–481 BCE) through the Han dynasty (206 BCE – 220 CE), bamboo or wooden slips were bound and used to write texts on. During the Eastern Han period (25–220), the use of paper and silk as handscrolls became more