Figure 3. Clock mechanism and its 4-in.-OD 

 pressure housing. 



Figure 2. Arrangement of steel bar reinforcement 

 for Spheres 17 and 18. 



Table 2. Hemisphere Dimensions and Out-of-Roundness Variations 



Item 



Mean 



Dimension 



(in.) 



Standard Deviation 



Maximum Local Variation 



Measured 

 (in.) 



Percent of 

 Wall Thickness 



Measured 

 (in.) 



Percent of 

 Wall Thickness 



Interior 

 radius 



E.xterior 

 radius 



Wall 

 thickness 



28.820 



32.943 



4.124 



±0.093 

 ±0.083 

 ±0.060 



±2.26 

 ±2.01 

 ±1.45 



+0.145 

 -0.213 



+0.150 

 -0.247 



+0.181 

 -0.165 



+ 3.51 

 -5.16 



+ 3.64 

 -5.94 



+4.26 

 -3.90 



Power was supplied to the clock from dry-cell Final assembly of the spheres is shown in 



batteries placed in a watertight, but not pressure- Figures 4 and 5. The descriptive information on 



resistant container located at the bottom of the Figure 5 gives important details on the assembly, 



sphere. When implosion occurs, the batteries are Documentation of the concrete material is given 



destroyed or shorted, and the lead wires running to in Appendix A. The mix proportions, compressive 



the clock are broken. strengths, cement compositions, and x-ray diffraction 



