82 ANNUAL OF SCIENTIFIC DISCOVERY. 



IMPROVED MOULDING SAND. 



Mr. ,T. W. "Winter, of Mnysville, Cal., recommends, in the Dental Neu-s 

 Letter, a new kind of moulding sand. He says : " Take equal parts of soap- 

 stone and Bristol brick, pulverize finely; mix. It is superior to any other 

 moulding sand, as it requires but little mixture to pack it firmly; and you 

 can get a finer impression, and can pour your metal at any stage of heat 

 without spoiling the die." 



NEW BRONZING PROCESS (FOR BRASS). 



A new bronzing process for brass has been introduced by Mr. Wagner.' 

 To obtain brass of a vciy deep -black color, he moistens the metal with a 

 dilute solution of " azotate of protoxide of mercury," and hs changes the 

 film of mercury thus formed on the surface of the article into the black sul- 

 pliurct of mercury, by washing it repeatedly with a solution of sulphuret of 

 potassium. If for the solution of the liver of sulphur, we substitute a solu- 

 tion of liver of antimony or of arsenic, a fine brass-colored bronze (" un 

 beau bronze de laiton") is obtained, varying in color from a deep brown to 

 yellow brown. He prepares the sulphurets of antimony or of arsenic by 

 boiling kermes (for the former) or of orpiment (for the latter) in a solution 

 of liver of sulphur. 



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NEW PROCESS FOR GILDING THREAD. 



Hitherto no other method has been known of producing " cloth of gold " 

 in the loom than using metallic threads, which render the tissue stiff and 

 heavy. By the process recently invented by the Messrs. Beurot, these ob- 

 jections are avoided. The silken or other threads are stretched close together, 

 and are then dipped into a solution of azotate (nitrate) of silver, to which 

 ammonia is added until the solution is perfectly limpid. After immersion 

 for one or two hours, the threads are dried, and then submitted to the 

 action of a current of pure hydrogen. The threads becoming thus metal- 

 ized, become also good conductors of electricity, and are then gilt by any 

 of the ordinary methods in use for electro-gilding. 



ON THE PROSPECTS OF STEAM TILLAGE. 



There is a certain little quiet philosopher who dwells in snug retirement 

 beneath the surface of our fields; he seldom shows himself abroad, because 

 he is aware that nature has behaved like a niggard towards him in the mat- 

 ter of personal graces. His eyes are small, dull specks, almost devoid of 

 organization; his face is a queer long muzzle, tipped at the end with a lump 

 of bone; his limbs are ungainly and short; and his coat is rough, and of un- 

 couth cut; yet, notwithstanding all these disadvantages, he is far from 

 repining. With a spice of practical wisdom that is beyond all praise, he 

 sets to work to make the most of the circumstances in which he finds him- 

 self placed. Sensible that he never could have been intended for a gay den- 

 izen of the daylight, he keeps himself close at home in his underground 

 retreat, and there contrives to turn strong arms, hard, brawny hands, a pair 

 of sharp ears, and a keen, sensitive nose, to excellent account. He bores 

 and delves for his living, and lucky indeed is the insect or worm that es- 

 capes his notice when his burrow chances to take the direction in. which it 



