434 TKANSACTIONS OF THE AMERICAN INSTITUTE. 



FORMATION OF SECTIONS. 



The Chairman appointed, as secretary of the Section of 

 Mechanics, S. D. Tillman, and as secretary of the Section of 

 Chemistry, Charles A. Seely. To the latter section was referred 

 Thomas' Kerosene Oil Burner, exhibited at the last meeting. 



PRESERVATION OF WOOD. 



Mr. Churchill read a paper on the preservation of wood for 

 railways; the statistics were obtained from tables on German 

 railroads in 1859, presented to the Institute by M. Vattemare. 



On sixty-four per cent, of the total mileage the wooden 

 sleepers, &c., were prepared. In new work, on two lines of 

 between 500 and 600 miles, chloride of zinc is being tried with 

 pine wood, ordinarily, oak is the material used and sulphate of 

 copper the general preservative. Creosote is only tried on a 

 short line, but the work, generally, is unsatisfactory. Recent 

 researches pointed ' to a longer immersion than that usually 

 employed as necessary; sulphate of copper combines with the 

 resin, and when long soaked with the nitrogenous part of the 

 wood, this has been entirely removed by M. Koenig, by using a 

 large excess of the salt. 



CRANK MOTION. 



Mr. Rowell again exhibited bis diagram, and explained his 

 theory. The common theory is that for every quantity of steam 

 admitted into the cylinder, there is produced an equal amount of 

 power at the crank. This theory supposes the connecting rod to 

 be always parallel to itself; but it will be found that in conse- 

 quence of the oblique motion of the connecting rod, it will fall 

 short of its place, and this will be a disturbing element. Again, 

 the first tenth of the stroke, the crank will be moved three 

 feet while the piston moves one foot, and consequently the power 

 cannot be so great. Upon the North river stearflboats, it may be 

 observed that at the half stroke there is a quick flutter of the 

 paddles in the water, while at the end of the strokes there is 

 almost a cessation of their motion. In order to use the steam 

 only in that part of the stroke where it is most efiective, I have 

 devised an adjusting piston to follow the regular piston at each 

 end of the cylinder, so as to allow the steam to propel the piston 

 for only 6-te ths of the stroke. 



Mr. R. exhibited a model of this contrivance, which was sub- 

 sequently referred t the Section of Mechanics. 



