BBIDGEPOET WOOD PINISHING 00. V. HOOPEB. 71 �is such that, in the process of filling, its particles are not farther pulverized to any appreciable extent, but are simply forced into the wood, from which they cannot be easily dis- lodged. Infusorial earth, on the other hand, is friable under pressure and friction, and bas a chalky rather than a gritty texture. It presents no angular fragments which can be rubbed into the pores of the wood, so as to fill them with an unabsorbent matcrial. �"Quartz is a crystallized silica of minerai origin, and, in common with ail crystals of such origin, bas no porosity that can be detected by the highest magnifier, and is, in mass, absolutely impenetrable to water, oil, or other similar liquids. Infusorial earth, on the contrary, is a hydrated silica that bas been organized into the structure of a plant, and, in common with ail vegetable tissues or organized structures, is porous and delicate in structure, so that, in respect to texture, hard- ness, sharpness, it is quite the opposite of powdered quartz in its applications as a wood ûUer. �"The fact that both quartz and infusorial earth consi8t,the first entirely, and the second largely, of silica, or the oxide of silicon, establishes no practical identity between them for the technical uses of the arts, and especially for use in wood filling, any more than the fact that the diamond and charcoal consist, esscutially, of carbon, proves the value of the dia- mond for fuel, or of charcoal as a gem." �The sand or si'ica found in silicious mari is, chemically, identical with pulverized quartz, "inasmuch as both consist of oxide of silieon or quartz, but, physically and practically, for the purposes of wood filling, different, because the sand mixed with infusorial earth, being a geologicai sediment, con- sists of rounded water-worn grains, while powdered quartz of the Wheeler patent consists of angular, sharp-edged frag- ments and splintcrs." �An attcmpt was made by Mr. Perry to show that he gave the patentee knowledge of the use of powdered quartz, but this defence is without foundation. �Let there be a decree for an injunction against the defend- ants, and for an accounting. ����
