;^THE ST. LOUIS ACADEMY OF SCIENCE. 723 



The length of each cover-section should correspond to the distance between 

 the centers of the supporting-columns. 



After the wires have been placed in position, any desired section of the con- 

 ducting chamber or the entire length thereof may be filled with parafifine, or other 

 insulating compound, but this is not essential to the perfect working of the line. 



It is evident from this construction that telegraph and similar wires may be 

 confined in a very limited space — for instance : a ten-inch conduit will accommo- 

 date two hundred wires, and their electrical condition and freedom from mutual 

 interruption will perhaps be more nearly perfect than those'of any known system. 



The described system affords absolute protection to life and property, for, 

 unlike the pole system, it will be impossible for a wire to break and fall from its 

 position in the conduit. 



The system will operate equally as well when constructed along the narrow- 

 est alley-way as upon the broadest streets — a fact of no small importance in the 

 construction and maintenance of a telegraph system. 



Improved Folding Table. — This invention consists, primarily, in construc- 

 ting the top of the table in two similar sections that are hinged together ; the ob- 

 ject being to produce a table that may be folded to the form of a small packing- 

 box. 



The construction may be described as follows : A pair of top-sections pro- 

 vided with raised border-strips which encircle the edge of each, hinges located 

 upon such strips for connecting the top-sections, a pair of rectangular supporting- 

 frames hinged to fold inward longitudinally upon the under surface of the top, 

 {their cross-bars resting in notches formed in the adjacent border-strips connect- 

 ing the top sections) and being severed upon a central line and provided thereat 

 with hinges to allow of a transverse fold in closing the top sections together, bi- 

 furcations in the lower extremities of the frames, and braces hinged to the under 

 surface of the top for engaging the bifurcations when the table is in use. 



The inventor is Mr. J. C. Mehaffey, of Kansas City. 



THE ST. LOUIS ACADEMY OF SCIENCE. 



In the meeting of the Academy of Science last week Prof. Pritchett gare a 

 description of his work in assisting in the compilation of the topographical map 

 of Missouri. His connection with the work was only as an astronomer, and the 

 Washington University Observatory was held throughout as the basis for all the 

 work. The uncompleted state of the work prompted a suggestion that an at- 

 tempt be made to obtain an appropriation from the State for its completion. The 

 value of such a showing as might be made of the mineral and agricultural re- 

 sources of the State, it was thought, ought to induce the making of the appro- 

 priation. 



Prof. Potter presented some analyses of water made to determine to what 

 extent sewage introduced into the rivers is oxidized and gotten rid of by oxida- 



