INDEX SLIP. 
PoYNTiNG, J. H., and Gray, P. L.—An Experiment in Search of a 
Directive Action of one Quartz Crystal on another. 
Phil. Trans., A, vol. 193, 1899, pp. 215-256. 
Gray, P. L., and PoYNTiNG, J. H.—An Experiment in Search of a 
Directive Action of one Quartz Crystal on another. 
Phil. Trans., A, vol. 192, 1899, pp. 245-256. 
Crystals (Quartz), Gravitative Action between. 
PoYNTiNG, J. H., and Gray, P. L. 
Phil. Trans., A, vol. 192, 1899, pp. 245-256. 
Gravitation Constant of Quartz; an Experiment in Search of Possible 
Differences. PoYKTiNG, J. H., and Gray, P. L. 
Phil. Trans., A, vol. 192, 1899, pp. 245-256. 
