Polytechnic Association. 639 



Mr. W. E. Partridge made an inquiry in relation to portions of the 

 head not supported by the stays. 



Mr. Wiard replied, and mentioned an instance in which the steamer 

 Narragansett had had its boiler broken in two by unequal expansion 

 before there was any pressure of steam upon it, and then had made 

 the trip before it was repaired. lie stated, also, that the boiler of one 

 of the Staten Island boats is now running with a rupture eight feet 

 long. 



Steam Canal-boat. 



Mr. D. L. Kennedy exhibited a model of a canal boat, 'with a pro 

 peller in front, taking in the water and passing it through two pipes, 

 and ejecting it at the stern. 



The President stated that the plan of passing the water through 

 the vessel was not new. In fact it was first proposed by the philoso- 

 pher Franklin. 



Dr. Van der Weyde — It was found that the friction of the water 

 in the pipes was so great as to counterbalance the apparent advan- 

 tages of the plan. 



Mr. Kennedy said it had not before been done in the same manner. 



Brush Machine. 



Mr. E. C. Woodbury, the inventor, explained the principle of the 

 machine exhibited by him at the fair, and exhibited portions ot 

 the apparatus and specimens of the work. No practical machines for 

 pushing or pulling the bristles into a brush-stock and making them 

 stay there, had been given to manufacturers till this of the Woodbury 

 Brothers was perfected. This country manufactures about 45,000,000 

 brushes annually. New York city has twenty-six brush factories, 

 and the total product of the metropolis is $2,000,000 worth annually. 

 These are made by hand-drawing — that is, bundles of bristles or 

 tampico arc by hand lashed about with a wire doubled dowm and the 

 end pulled through the holes of the brush-stocks. The wire is then 

 fastened to another on the back of the brush, and, after all the holes 

 are filled, a false back of veneer is screwed or glued over the wires. 



The Woodbury machine abolishes all this hand labor, and effects 

 the insertion of the material wholly by steam-driven machinery. A 

 quantity of the bristles is laid upon a comb-shaped feeder, and a steel 

 point parts from the edge of the bristles, as spread upon the apron, 

 just enough for one bunch. A plunger comes down upon this bunch 

 and bends it double, the two halves fitting into slots in the follower in 



