The present invention provides a method of manufacturing a golf ball having a solid core formed of a rubber composition and a cover of at least one layer encasing the core, which method includes the steps of treating a surface of the core with a solution containing a halogenated isocyanuric acid andor a metal salt thereof, and covering the treated core with a cover material. The filtered air is produced from the filter as a result of the membrane removing any hydrocarbons containing six or more carbon atoms to produce a total of 0. Further, the manufacturing method of the resin for wet friction materials includes a step of reacting phenols with aldehydes in the presence of at least one basic catalyst to obtain a water-soluble phenolic resin having a predetermined water percentage. The system also includes an outcoupling radiation propagation portion for coupling out an idler radiation beam generated in the bent structure. The processor determines over which section the object is positioned by comparing the signals from the sensing channels, and determines the position of the object within that section by comparing the signals from the terminals spanning that section.