BBIDGKPOBT WOOD FINISHINO CO. V. HOOPER. 67 �thus obtained prodnces the most effective agent for the pur- poses of the cabinet maker, producing a more perfect polish upon the surface of the wood, and being more ëasily and conveniently applied tban any other material for this objeot in use. �" The advantages obtained by the use of this substance are very important, especially to manufacturers on a large scale, where cheapnesB of material in an agent so extensively used ai this class, to which my invention belongs, makes Buch a vast dif- ference in the profits of the trade. This earth being often found in large quantities, and then the superior qualities it has in polishing and filling wood, render it of great value to the cabinet maker, carriage maker, and others in similar occupations. �"Now, having described my invention, what I daim as new, and desire to secure by letters patent, is : First, the use of silicious mari or inf usorial earth for the purpose of filling and polishing wood, substantially as herein set f orth ; and, second, the combination of silicious mari with any or ail of the sub- stances herein named, sulphate of zinc, muriate of ammonia, gum arable, gum tragacanth, and oil, substantially in the manner and for the purpose herein set forth." �The Perry article, as described in bis patent, is not now used, and, in my opinion, is not valuable. �The theory of the defendants is this : Flint and quartz are chemically silica, more or less pure, or what is known to chemists as silicic acid. Feldspar is a silicate of alumina and potash, and contains silica in large proportions. Quartz and flint contain from 85 to 100 per cent, pure silica. Infu- Borial earth is a fine-grained earth, formed by the deposition of the silicious coatings or shells of microscopic plants called infusoria, on the bottom of ponds or lakes of water, and is lifostly silica mixed with carbonate of lime and other impu- rities. Silicious mari is a mixture of clay and carbonate of lime and silica in the form of sand or infiisorial shells. Si- licious mari contains from 20 to .50 per cent, of silica. As, therefore, quartz or flint contains from 85 to 100 per cent, of silica, and infusorial earth and feldspar are mostly silica; ����
