102 ANNUAL OF SCIENTIFIC DISCOVERY. 



The syrup from the boilers is filtered, the excess of lime sepa- 

 rated by carbonic acid, and it is further concentrated and finished 

 in the usual manner. The slimy residues and precipitates are 

 squeezed out in filter presses until they contain no trace of sugar, 

 and can be thrown away. The wash-water is used in the prepa- 

 ration of new material. The advantages of this new process are, 

 that it does away with the use of blood, which is offensive, diffi- 

 cult to obtain, and the soluble constituents of which are finally 

 concentrated in the molasses. 



It also yields greatly improved products, which are brighter in 

 color, and better in grain. The third crystallization of this 

 process is better than the second in the old way. The expense 

 is, if anything, less, certainly not more. The process has been 

 patented in the United States. 



APPLICATION OF DIFFUSION IN SUGAR-REFINERIES. 



Abbe Moigno states that in the years 1869-70 the number of 

 sugar-houses in which the principle of diffusion or dialysis was 

 employed for refining sugar was 82, and that 31 additional works 

 are in process of construction; so that in 1871 there will be 113 

 refineries in which practical application will be made on a large 

 scale of Graham's important law. The crystallizable sugar passes 

 through membranes, while the impurities, being uncrystallizable, 

 are retained in the tank where the original solution was made. 

 The fact that so many large houses employ this method would 

 seem to indicate its entire practicability. 



PHOTOGRAPHY ON WOOD. 



Anthony's ' Photographic Bulletin" gives the following process 

 by A. J. Searing for photographing on wood for engraving pur- 

 poses : 



" The block on which the picture is to be made is first dampened 

 with water, then whitened with enamel, rubbed from the surface 

 of good enamelled visiting-cards. Rub gently, removing only 

 the enamel, after which it is brushed smooth with a moderately 

 stiff brush, from right to left and up and down, making a smooth, 

 even, and very thin surface. Allow this to dry, after which it is 

 flowed with a solution of albumen, made with the white of 1 egg 

 and 16 ounces of water, dried by heat or allowed to dry spontane- 

 ously. Now coat it with another albumen solution made as fol- 

 lows : 



Formula No. 1. White of 1 egg; water, 4 ounces; chloride 

 of ammonia, 40 grains. Beat the whole to a thick froth. Allow it 

 to subside, then decant or filter through a fine sponge placed in a 

 glass funnel. Pour a sufficient quantity on one corner of^the 

 block to cover it, when spread around with the aid of a one-ninth 

 or one-sixth glass (using the edge) . Allow the surplus solution 

 to drain back into the bottle. Dry by a gentle heat. 



Formula No. 2. Ether, 1 ounce; alcohol, 1 ounce; gun- 



