2GG 



ANNUAL OF SCIENTIFIC DISCOVERY. 



Properties of ordinary oxygen in the 

 free state, and at the temperature 

 o/15 C. (60 F.) 



Has no action on ammonia. 



Has no action on pbosphuretted hy- 

 drogen. 



Does not decompose iodide of potas- 

 sium. 



Has no action on hydrochloric acid. 

 Has a feeble oxidizing action. 

 Very stable at all temperatures. 



Properties of nascent oxygen in the 

 free state, and at the temperature 

 of 15 C. (60 F.) 



Burns ammonia spontaneously, and 

 transforms it into nitrate. 



Instantly burns phosphuretted hydro- 

 gen, with emission of light. 



Acts readily on iodide of potassium, 

 setting the iodine free. 



Decomposes hydrochloric acid, set- 

 ting the chlorine free. 



Is a powerful oxidizing and chlorin- 

 iziug agent. 



Stable at 15 C., but destroyed towards 



75. 



Peroxide of barium is not the only body which is capable of yielding active 

 oxygen. Oxygen in the combined state possesses, indeed, the intensified 

 power which distinguishes free oxygen in the nascent state, and which it 

 ceases to exhibit when completely isolated, because the temperature at which 

 it is usually evolved from its combinations is equal or superior to that at 

 which active oxygen passes into the ordinary state. 



WATER-GLASS. 



The following is an abstract of a recent report of a commission appointed 

 by the French Government to examine the several processes devised by M. 

 Kuhlmann, of Lille, for the employment of soluble alkaline silicates for hard- 

 ening stone, painting, etc. 



Theory of Hydraulic Cements. The silicious solution, silicate of potash or 

 silicate of soda, forms the basis of all the new processes. Since 1840, 

 researches upon the origin and nature of the efflorescences upon walls have 

 furnished Mr. Kiihimann with the opportunity of ascertaining the presence of 

 potash and soda in most of the limestones of the various geological epochs, 

 in larger proportion in hydraulic limestones than in fat limestones (a c.haux 

 g7-asse). What would be their influence upon the hydraulic properties of the 

 lime? Mr. Kiihimann thought that, under the influence of potash or soda, 

 silicious limestones might give origin, when calcined, to double compounds 

 of lime, silica, or alumina, and an alkali analogous to those which would be 

 obtained by the calcination of some kinds of hydrated minerals, and that 

 these compounds, when afterwards brought into contact with water, would 

 undergo an action analogous to that which causes the consolidation of plas- 

 ter, viz., hydration, and at last perfect hardness. 



The principal effect of the potash and soda would consist in transferring a 

 certain quantity of silica to the lime, and in giving origin to silicates, which 

 absorb water with avidity (so as to leave only that portion of water neces- 

 sary to their hydrated nature), and become solidified. Numerous facts bore 

 out this theory. Quicklime, when left in contact with a solution of silicate 

 of potash, is immediately transformed into hydraulic lime. Quicklime and 

 an alkaline silicate, very finely pulverized, and mixed in the proportion of 

 eleven of silicate to one hundred of lime, likewise furnish an excellent 



