a specially designed torch created by the Institute of Gas Technology with an electrical ignition which kept the flame lit in wind or rain and which fed the gas oxygen to create the correct color. A debate broke out between providers of bottled propane gas and line-fed natural gas as to which source of fuel should be used to supply the eternal flame. The debate was so vigorous that it broke out in public in March 1964. The cost of construction of the approaches, elliptical plaza, walls were estimated at $1.77 million in February 1965. The cost of construction of the actual grave site was estimated at $309,000. Fifteen firms were invited to bid on the construction contract and nine did so. A $1.4 million contract for construction was awarded to Aberthaw Construction in mid-July 1965. The Army Corps of Engineers consulted with the Kennedy family before letting the award. A second contract for structural design consulting in the amount of $71,026 went to Ammann & Whitney. At this time, contracts for the quotation inscriptions, the marble base for the flame, the bronze brazier, and the slate markers had yet to be let. The white marble for the plaza, terrace, and steps came from Proctor, Vermont, and the granite for the approaches came from Deer Isle, Maine. Prior to construction, several design changes were made to the Kennedy grave site. The retaining wall behind the grave was removed, and the hill landscaped to allow an unobstructed view of Arlington House. Concerned that the grass on the burial plot would wither in Washington's hot summers, in the fall of 1966 the decision was made to replace the grass with rough-hewn reddish-gold granite fieldstone set in a flagstone pattern. The fieldstones used had been taken more than 150 years ago from a quarry on Cape Cod near where Kennedy used to spend his summers. The burial plot, originally designed to be raised a substantial height above the surrounding terrace, was lowered so that it was just three to four inches higher. The bronze brazier shape for the eternal flame was also replaced. Instead, a wide beige circular fieldstone (found on Cape Cod in 1965) was set nearly flush with the earth and used as a bracket for the flame. Construction of the approaches required regrading the hill. Crews were forced to work with picks and shovels around the oak tree to protect