804 Transactions of the American Instituie. 



PROCEEDINGS 



POLYTECHNIC ASSOCIATION. 



A Society Okoanized by, and under the Control 

 OF, THE American Institute. 



The Polytechnic meetings are held weekly for the purpose of 

 examining new inventions and discoveries, and discussing topics 

 appertaining to Technology. 



May 6, 1869. 



Samcel D. Tillman, LL.D., ia the chair; C. E. E^rERY, Esq., Secretary. 



The proceedings were varied and interesting. At the opening of 

 the meeting Mr. Schmidt exhibited a model of what may be termed 

 a submerged bridge or tubular passage-way, proposed as a means of 

 crossing the East river. It is designed to make the structure of 

 wrought-iron, braced internally by suitable frame-work, and formed 

 in sections of suitable length. These sections joined together, the 

 inventor claimed, could be sunk in the river at such depth as not to 

 interfere with navigation, and yet at such a distance from the bottom 

 as to secure the least possible inclination in descending to and 

 ascending from the tubular passage-way constituted by the structure. 



Sanitary Paint. 

 Mr. Thomas Ilodgeson, of Brooklyn, N. Y., presented several 

 articles coated with a paint, which he said was not poisonous. The 

 ingredients are somewhat similar to his composition for making 

 artificial stone, which was exhibited at a recent meeting. The basis 

 of the paint is composed of oxalic acid and lime, or alum, in com- 

 bination with feldspar, or any of the substances containing alkaline 

 earths. 



