316 ANNUAL OF SCIENTIFIC DISCOVERY. 



recently made investigations into the qualities of several woods to 

 ascertain which was the best for ship-building purposes. " If English 

 oak," he said, " has hitherto stood so high, it must have been owing to 

 our ignorance of the valuable properties of sonic of the woods groA^n 

 in tropical climates, in which the soluble and highly decomposable 

 tannin of oak is replaced in some instances by resins, and in others by 

 substances similar to caoutchouc. This is the case with East Indian 

 teak, Mora wood, Santa Maria and Honduras mahogany, which give 

 them great advantages over oak when used for ship-building." 



The liability of different woods to dry-rot were arranged by Dr. 

 Calvert as follows : Unseasoned oak, rapid ; seasoned, moderately 

 rapid ; African teak and Honduras mahogany, limited ; Mora wood, 

 Santa Maria mahogany, and Indian teak, no tendency whatever to 

 dry-rot. 



It was also observed by Dr. Calvert that oak which was felled in 

 summer contained but little tannin and a great deal of gallic acid, 

 while that felled in winter was rich in tannin and contained very little 

 gallic acid. 



Iron as a Tonic in Horticulture. According to a Belgian horticul- 



^j ^2 



tural paper, a Mr. Dubreuil, acting upon the experience that the 

 leaves of a plant may be stimulated into a luxuriant growth by being 

 moistened with a solution of copperas, applied a weak solution of this 

 salt (half a drachm to a quart) to various kinds of fruit at a time of day 

 when the same could not be reached by the rays of the sun, and at 

 three different periods before their maturity. The first so treated are 

 said to have grown to an extraordinary size. 



White Flowers. M. Filhol, the celebrated French chemist, in a 

 paper on the coloring matter of flowers, states that there are no flow- 

 ers of a pure white existing. The celebrated painter Redout noticed 

 this a long time since. Flowers which appear to us white have nearly 

 always a light-yellow, rose-colored, or blue tint. All these flowers 

 become of a fine yellow when dipped in ammonia. Acids restore 

 their primitive color. 



PERENNIAL COTTON. 



Mr. R. C. Kendall, of Maryland, in a recent pamphlet, calls atten- 

 tion to the existence, in Chili, S. A., of a species of cotton-bearing 

 plant or tree, perennial in its nature, and capable of being grown 

 with profit wherever Indian corn will ripen. His first acquaintance 

 with the plant or tree in question was made while exploring the course 

 of a little mountain stream, the Chipura, in Southern Chili. He 

 says : " Doubling an abrupt turn in the course of the river, I came 

 suddenly into full view of an object, some two hundred yards distant, 

 which presented the most magnificent spectacle I had ever seen a 

 perfect cone or pyramid of pure, brilliant snow, elevated at its base 

 perhaps seven feet from the ground, upon a shaft of whitish bronze ; 

 the whole structure cut clear and sharp against the dark wall of rock 

 in the background. It resolved itself, as I drew near, into a most 

 perfect specimen of the Gossypium arboreum, the perennial cotton- 

 tree. Its foliage had long been shed, but the pods remained, having 

 fully burst, and turned out their spotless samples in almost perfect 



