In the meantime many detailed plans of stonework for the exterior walls, foundations, etc., had been prepared, and the working up of the details of design and construction in general had been actively going on in the drafting room, so that all was in readiness for the prompt and vigorous commencement of operations, which took place on the ground as soon as Congress had passed the act of March 2, 1889. In the execution of the work General Casey had the entire responsible charge under Congress from October 2, 1888, until his death, on March 25, 1896, and he also disbursed the funds during that period. He held general supervision, gave general direction to all principal proceedings, and maintained an intimate knowledge of the work at all times, while performing the duties of his more absorbing and important office of Chief of Engineers of the Army at the War Department, to which he succeeded a few months before he was placed in charge of the Library building by Congress. General Casey had been connected with some of the most important pieces of construction ever undertaken by the Government, including the erection of the State, War and Navy Building and the completion of the Washington Monument. The last was an especially difficult task, as it had been necessary to strengthen the old foundations of the shaft before it was possible to proceed with the work. In this delicate and hazardous undertaking, as well as in the erection of the State, War and Navy Building, and other works, General Casey had been assisted by Mr. Bernard R. Green, C. E., whom he now appointed to be superintendent and engineer of the construction of the new Library building, and put in full local charge of the entire work. To aid in designing the artistic features of the architecture--that is, exclusive of arrangement, construction, utility, apparatus, and the management of the business--Mr. Paul J. Pelz was employed under the immediate direction of General Casey and Mr. Green. Mr. Pelz had been in partnership with Mr. Smithmeyer in the production of the original general plan and design. In this way the design of the building, as it now appears in the main in the exterior and court walls, the dome, the approaches to the west front, was evolved, Mr. Pelz thereby fixing the plan and main proportions of the building. In the spring of 1892 Mr. Pelz’s connection with the work ceased. At that time the building had reached but little more than one-half its height.