SAWDUST. The waste made by sawing timber, formerly of little or no use, has now become a material of some value in localities where it car. be applied. Its mostinterest ing application is one very recently patented by Messrs. Dale & Co. of it is converted into oxalic acid, and with so much suecess as to have nearly or altogether displ iced every other method of making that chemical. The process is very 'simple. The sawdust is first saturated with a concentrated solution of soda and potash in the proportion of two of the former to one of the latter; it is then placed in shallow iron pans, under which flues run from a furnace, whereby the iror. pans are made hot, and the saturated sawdust runs into a semi-fluid pasty state. It is stirred about actively with rakes, so as to bring it all in contact with the heated surface of the iron, and to granu late it for the succeeding operations. It is next placed in similar pans, only slightly heated. by which it is dried. In this state it is oxalate of soda mixed with potash. It is then placed on the bed of a filter, and a solution of soda is allowed to percolate through it, which carries with it all the potash, leaving it tolerably pure oxalate of soda. It is
then transferred to a tank, iu which it is mingled with a thin milk of lime, by which it is decomposed, the lime combining with the acid to form oxalate of lime, and the soda being set free. Lastly, the oxalate of lime is put into it leaden cistern, and sulphuric acid is poured in ;• this takes up the lime, and sets free the oxalic acid, which readily crystallizes on the sides of the leaden cistern, or MI pieces of wood placed on purpose. So raphl and cheap is this method, compared with that formerly use, that several extensive manufactories for making oxalic acid in the old manner have been shut up, being unable to compete with the patent process.
Another interesting use of the sawdust of hard woods, such as rosewood, ebony, etc., is that recently made known in France under the name of Boiedurci. lho various kinds of sawdust used are reduced to fine powder, and mixed with blood into a paste; other materials are doubtless added, for when pressed into molds it is jet black and receives the most beautiful impressions. Messrs. Larry, Senior & Co. of Paris produce some very beautiful medallions and other small articles in thismaterial.