Proceedixgs of the Polytechxic Association. 881 



Wi^'DiNCr Staiks. 



Mr. "W. I. Keiiiis exliibited models of his various styles of windinp- 

 stairs. There were double and triple pairs of stairs ; the whole could 

 be revolved, as tlie center ])ost rested on a pivot. Persons could 

 ascend one pair of the stairs while others W(juld be descending the 

 other. The stairs were claiuied to be self-supportini!;. 



Mr. C. E. Emery admired the ingenuity of the staircase, but stated 

 that it was not as strung as it a[)peared. The actual base of the 

 structure was equal to the width o'i one stair only. 



OuiNoco Valley. 

 Dr. Tl. P. Stevens read a paper on the scetiery and products of the 

 Orinoco A^alley, of wlvich no report has been furnished. 



Adjourned. 



November 25, 1869. 



Professor S. D. Tillman in the chair ; C. E. Emery, Esq., Secretary. 



The Chairman opened the proceedings by reading the following 

 notes on science : 



A Milk Mushroom. 

 M. Ilesling states, in the Journal de Pharmacie et de Chimie, that 

 even long before milk becomes sour, there are generated in it very 

 small organized spores of an ascophora species. 



C'oxsuMixG Smoke. 

 A contrivance for consuming smoke has been invented in Penn- 

 sylvania. It consists of a box containing a fan, attached to the lire- 

 box of an engine, so as to catch smoke and drive it back into the 

 furnace, where it is* consumed. Thus a large saving of fuel is 

 eflected and tlic smoke nuisance is abated. 



Ax Electrical Ixskct. 



It is reported, on the authority of the late Major-Gcneral Davis, 

 of the lioyal Artillery, that the liediivius scrmtus, commonly known 

 in the "West Indies as the '' wheel bug," can, like the Gymnotus 

 electriciis, con)municate an electric shock to the pci'son whose flesh 

 it touches. ^^..-_ [ 



[Inst.] 56 



