Non-Magnetic Experiment Building 357 



Cement Stucco. To be made up and applied in 3 coats in accordance with the recommended 

 practice for Portland cement stucco issued in 1919 by the American Concrete Institute's committee 

 on the treatment of concrete surfaces. Exposed aggregate to be granite and mica and treated as 

 directed. Lathing, needed in gable of porch only, must be of wood nailed with copper nails. 



Lumber. Structural wood work, nailing blocks, furring strips, tongue-and-groove stuff for 

 overhang, etc., must be of No. 1 well-seasoned Georgia pine or cypress. Tongue-and-groove stuff 

 for roof sheathing to be well-seasoned Virginia pine. 



Mill-Work. All sash and doors to be of cypress 1%-inch thick. Window and door frames 

 and outside wood sills to be of No. 1 well-seasoned Georgia pine. All other interior trim to be 

 No. 1 cypress. All sash and doors to be glazed with AA double-thick glass (zinc points to be used). 

 No shutters are to be provided. 



Hardware and Metal Work. All metals used must be non-magnetic brass, copper, zinc, or 

 lead, including nails, lag-screws, wood screws, pipes (inside and to all points within 40 feet of the 

 outside of building), locks, lifts, sash pulleys, sash weights, etc. Rabbeted-face locks and flush 

 bolts to be provided for the 2 entrance doors. All down-spouts, gutters, and flashings to be of 14- 

 ounce copper. 



Plumbing. Sink to be of 1% white pine lead lined with lj^-inch waste to connect with sewer 

 at main building and to be properly vented. Down-spouts to be connected to salt-glazed terra- 

 cotta tile to grade at culvert. Cold-water, hot-water, gas, and compressed-air mains from main 

 building are to be %-inch, %-inch, 13^-inch, and 1-inch respectively. 



Electric Work. Wiring and conduits for alternating-current and direct-current from main 

 building are to be as shown by detail sheets. 



Heating. Low-pressure, single-pipe, return system from "Ideal" cast-iron boiler in main 

 laboratory basement room (another section to be added to boiler) ; supply main 3-inch pipe to be 

 carried in tunnel, return l}-^-inch pipe, in accordance with detail drawings. All radiation and 

 piping within 40 feet of the Experiment Building to be copper or brass. 



MAGNETIC SURVEY OF BUILDING. 



In the course of construction observations at different levels and at different points 

 were made from time to time with compass-variometer No. 2 to guard against use of 

 any magnetic material in the construction. At no time during the course of construction 

 were any appreciable magnetic effects observed. 



During March 12 to 24, 1920, a detailed magnetic survey of the interior of the finished 

 structure, with permanent fixed equipment in place, was made by Messrs. W. F. Wallis 

 and A. Sterling. The observations were made at 9 stations inside the building, and at 

 2 heights above the finished floor at each station. These stations were at the inter- 

 sections of 3 north-south and 3 east-west lines, parallel to the length and width of the 

 building, respectively, the eastern-most and northern-most lines being 6 feet 1 inch from 

 the inside east and north walls; the second and third length-lines of stations were 12 feet 

 1 inch and 18 feet 1 inch, respectively, from the east wall, while the second and third 

 east-west fines were 24 feet 1 inch and 42 feet 1 inch, respectively, from the north wall. 

 While observations were being made at these stations by one observer, the other observer 

 at a tenth station made simultaneous observations with his instrument, mounted on its 

 regular tripod, to obtain data for the elimination of diurnal-variation effects. This tenth 

 station was designated as E8, and was in the north-south line of stations on the east side 

 of the building, 6 feet 1 inch from the east wall and 2 feet 5 inches from the south wall. 



The observations were made with C. I. W. magnetometer-inductors Nos. 24 and 26, 

 No. 26 being used at E8 and No. 24 at the other stations. The 9 points above described 

 were designated El, E4, E7, Ml, M4, Ml, Wl, W~4, and W7, with the additions of the 

 words low or high to indicate the station at the low level, when the suspended magnet 

 was 1 foot above the floor, or at the high level, when the magnet was 3.4 feet above the 

 floor. It had been planned originally to observe at intermediate stations on the north- 

 south fines, to be spaced 6 feet apart and to be designated by the numbers 2, 3, 5, and 6, 

 but the observations soon showed such uniformity in the magnetic field inside the 

 building as to make additional stations unnecessary. 



