After Mr. Gray's investigations, Messrs. Mackin and Dillon (F. H. Dillon, Assoc. M. Am. Soc. C. E.), under contract with the Government, prepared the following plans: For a dam in the Santa Catarina Canon; for a pipe line, similar to the one proposed by Mr. Gray, to a reservoir and settling basin on the left bank of the river (a short distance above where the provisional pumping station was established afterward by Mr. Binckley), but on the flat above the bluff skirting the river, practically at the same elevation as the present high-pressure reservoirs; for a complete network of water mains and sewers in the city, indicating the approximate direction in which the sewage would be disposed of, either by turning it into the river or by spreading it over suitable lands, the location of which was to be determined later; and also a complete set of specifications. On these data bids were invited by publication, and inquiries were received from several parties. Finally, Messrs. Stocker and Walker, of Scranton, Pa., entered into negotiations with the Government, and the present concession was agreed upon and granted. Messrs. Stocker and Walker engaged the late E. Sherman Gould, M. Am. Soc. C. E., to prepare a plan for a storage dam in the Santa Catarina Canon, and submitted plans for water distribution and sewers in the city, slightly modifying the original plans of Messrs. Mackin and Dillon. In the fall of 1905, the concession was acquired by Messrs. Mackenzie, Mann & Co., of Toronto, Canada, together with all plans, etc., presented by the original concessionaires. The new concessionaires stated that they would examine the whole situation again, for the purpose of presenting modified plans for works.