2-12 ANNUAL OF SCIENTIFIC DISCOVERY. 



far more rapidly when hot than cold, it certainly can be saved, and the pro- 

 cess accelerated, by bleaching in tight boxes heated by steam. 



Bkaching Paper Pulp. M. Didot, of Paris, has prepared the following new 

 method of bleaching paper pulp: He immerses the pulp in a solution of 

 bleaching liquor, which is made by saturating chloride of lime in water, and 

 using the clear liquor, and then passes carbonic acid gas through it. It is 

 stated to be an improved process for bleaching both pulp and textile fabrics. 



Bleaching Straw Pulp. In the specification of a patent lately granted to 

 J. Cowley, and D. P. Sullivan, of England, it is stated that in bleaching straw 

 pulp, the liquor (chlorine) used is about one and a half to two degrees in 

 Twaddle's hydrometer, in strength ; that a lower strength will not bleach the 

 pulp, and a stronger liquor will injure it, and not produce so good a color. 

 When the straw is undergoing bleaching, it is carefully watched, and as soon 

 as it assumes a reddish color, just merging on the white, a jet of steam is 

 cautiously let on and continued for two hours, until the liquor has attained to 

 a blood heat, or about 90, at which temperature it is maintained for about 

 two hours longer, when the straw will be completely bleached, and fit for 

 the beating engine. Unless the steam is gradually introduced, the color will 

 not be good. 



ON THE GUANOS OF THE ATLANTIC. 



At a recent meeting of the Boston Society of Nat. His., Dr. A. A, Hayes 

 presented the following paper on the Guanos of the islands of the Atlantic 

 Ocean. 



About two years since, an enterprising commercial firm in Boston dis- 

 covered on Monks Island, a small island off the coast of Guiana, a remarka- 

 ble rock, covering a deposit of the kind of guano now so well known, as 

 coming from the Atlantic side of South America. The rock and guano were 

 sent to me for chemical analysis, and finding both to possess a high economi- 

 cal value, I recommended the introduction of them as sources of phosphate 

 of lime, for agricultural purposes. A large quantity of these products has 

 been imported, and numerous analyses by myself and others have shown a 

 considerable uniformity in the composition of thousands of tons. 



In the specimen which I have called Guano Rock, we have irregular 

 incrustations of from one inch to two feet in thickness, pale yellowish brown, 

 or nearly white, while its fracture is of some shade of dark brown, and showa 

 bands of very dark, alternating with those of a lighter color. Like compact 

 calcareous concretions, the upper surface presents rounded elevations and 

 nodules, while below the mass is full of cavities and irregularities. Its frac- 

 ture is generally splintery, and its average hardness, greater than that of 

 Fluor spar, is next to that of Feldspar. Sp. Gr. 2*440 (average). 



The arenaceous guano may be considered as comminuted fish bones, mixed 

 with minute shells, still retaining organic matter ; and one of the specimens 

 shows the first step in aggregation, by which solid masses form. These 

 eventual^, by chemical operations, become consolidated, so that the resulting 

 body has all the characters of a firm rock. The rounded grains of the arena- 

 ceous guano are g-or-orally of the size of mustard seed, and in forming the 



