CI 





forced slightly open by tlie pres- 

 ence of the iniiowing current — is 

 attached to the lower extremities 

 of the long strips or pieces, g g^ g^ 

 arranged to slide upward through 

 mortices in the beam, a. The lat- 

 ter, in turn, is provided at each end 

 with trunnions fitting loosely into 

 corresponding sockets in the up- 

 rights _^9, p^ by which means the 

 beam and its dependent ^jarts are 

 allowed to swing readily in place, 

 as indicated by the j)ositions of the 

 gate or valve in the several dia- 

 grams. 



Another and fixed beam, indi- 

 cated at./, serves as an additional 

 sup|)ort to the uprights, p^ p ; and 

 as the fulcrum of a lever by means 



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