1 calorie of heat is the amount needed to raise 1 gram of water 1 degree Centigrade. 1 calorie (cal) = 4.184 J. (The Calories in food ratings are actually kilocalories.) A BTU (British Thermal Unit) is the amount of heat necessary to raise one pound of water by 1 degree Farenheit (F). 1 British Thermal Unit (BTU) = 1055 J (The Mechanical Equivalent of Heat Relation) 1 BTU = 252 cal = 1.055 kJ.
San Antonio River Walk. A couple strolls along the River Walk. The San Antonio River Walk (also known as Paseo del RÃ­o or simply as the River Walk) is a network of walkways along the banks of the San Antonio River, one story beneath the streets of San Antonio, Texas, USA.
By Hugh Hemphill, author of San Antonio On Wheelsand The Railroads of San Antonio and South Central Texas.. This chapter focuses on the development of roads and bridges in San Antonio from the first bridge over the river up to 1944. As early as 1775, there were three categories of roads in Texas.