1975

Designated an Historic Landmark in Honor of J. Brownlee Davidson a Founder of Agricultural Engineering First President of American Society of Agricultural Engineers Organizer of the First Professional Agricultural Engineering Curriculum July 1905 by American Society of Agricultural Engineers

When first proposed in 1819, the Hoosac Tunnel seemed so logical. It would provide an efficient and direct route for the Boston and Albany Railroad, whose pathway meandered 20 miles along precipitous grades. Early proponents, however, could not have imagined that blasting a 4.75 mile tunnel through the Hoosac Mountain would require over 20 years of labor. The project took so long to complete that it was commonly referred to as "The Great Bore." 

The Granite Railway Company of Quincy was the first commercial railway in the United States. Incorporated in 1826 and designed by Gridley Bryant, the railway relied on horses, rather than steam locomotives, to draw the cars along the tracks. Its primary purpose was to transport granite from Quincy to build the Bunker Hill Monument. 

This majestic viaduct was built during the golden age of railroading. It was at the western end of a major readjustment in grade and alignment of the Erie-Lackawanna Railroad, and had double tracks to carry the trains across the valley of Tunkhannock Creek. The Hallstead cutoff (between Scranton, Pennsylvania and Hallstead, New Jersey) reduced passenger travel time by 20 minutes, and freight travel time by over an hour.

Three rivers - the Allegheny, Monongahela, and Ohio - join in Pittsburgh, making the city a natural site for the building of bridges. But the Smithfield Street Bridge stands apart from other Pittsburgh bridges for several reasons: it replaced structures by two well-known bridge engineers, Lewis Wernwag and John A. Roebling; it was the first use in America of the lenticular - or lens-shaped - truss design; and it was one of the first major bridges in the U.S. built primarily with steel.

The economic situation in the whale oil business (for lighting), coupled with the increased demand for lubricants, stimulated growth in the U.S. petroleum industry. The drilling of the heavy, sulfurous, and asphaltic California crude began in the 1870s at the Pico Canyon area, using the apparatus and techniques from Titusville, Pennsylvania, developments.

Some of the station's notable achievements:  
The first method for detecting radioactive particles in water supplies  
A successful system of slow-sand filter beds for drinking water  
The landmark demonstration that microorganisms carried within filter media could degrade sewage 

"The State [of California] agreed to construct the dam using convict labor for which consideration the State received a grant of land for the construction of a prison and water power rights from the impounded water ...; The work progressed slowly during the dry season by disinterested convict labor using hand tools since the use of machinery was forbidden ...;"  
- Historic Landmark Nomination Form, 1974

Inferior water and the lack of a sufficient water supply prompted public pressure to find a significant water source for the 360,000 of people living in New York City at the time. Studies determined that the Croton River, 40 miles north of the city, was the best available source. The original system served as a prototype for large-scale water supply projects across America. 

The fort was constructed of coquina rock. Unique to Florida, the rock consists of millions of seashells cemented together. It proved highly durable and easily absorbed the force of many cannon balls. 

The Castillo de San Marcos was the first permanent European settlement in the continental United States. Originally an outpost of the Spanish Empire, it is the oldest major engineered structure existing in America.