and chewy texture. Cones Mrs A.B.Marshall's Cookery Book, published in 1888, endorsed serving ice cream in cones. Agnes Marshall was a celebrated cookery writer of her day and helped to popularize ice cream. She patented and manufactured an ice cream maker and was the first to suggest using liquefied gases to freeze ice cream after seeing a demonstration at the Royal Institution. Reliable evidence proves that ice cream cones were served in the 19th century, and their popularity increased greatly during the St. Louis World's Fair in 1904. According to legend, an ice cream vendor at the fair ran out of cardboard dishes. The vendor at the Syrian waffle booth next door, unsuccessful in the intense heat, offered to make cones by rolling up his waffles. The new product sold well and was widely copied by other vendors. Cryogenics In 2006, some commercial ice cream makers began to use liquid nitrogen in the primary freezing of ice cream, thus eliminating the need for a conventional ice cream freezer. The preparation results in a column of white condensed water vapour cloud. The ice cream, dangerous to eat while still "steaming" with liquid nitrogen, is allowed to rest until the liquid nitrogen is completely vaporized. Sometimes ice cream is frozen to the sides of the container, and must be allowed to thaw. Good results can also be achieved with the more readily available dry ice, and authors such as Heston Blumenthal have published recipes to produce ice cream and sorbet using a simple blender. See also Cold-stimulus headache Ice cream social List of dairy products List of desserts List of ice cream brands List of ice cream flavors Milkshake (a blended mix of ice cream, milk and syrups) Nancy Maria Donaldson Johnson Soft serve References External links How It's Made: UConn Dairy Bar Ice Cream Selected Internet Resources – Ice Cream / Science Reference Section, Library of Congress Dairy products Types of food Frozen desserts World cuisine Independence Day (United States) foods