PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 477 



ing will change it. The injurious effects of wearing a hat not made to the 

 shape of the head, can readily be perceived, as the whole weight of it 

 rests upon three or four points of the head and stops the circulation of the 

 blood, thus giving rise to headaches, or an uncomfortable feeling generally. 

 By taking the shape of the head with this instrument, a hat can be made 

 to fit exactly the various outlines of the skull and giving perfect ease and 

 comfort to the wearer. The French conformater is used by pressing it 

 down upon the head when the various levers or pins adapted themselves to 

 its shape. This mode is disagreeable, as at times the violence with which 

 it is forced down upon the head gives considerable pain. In this instru- 

 ment the process is very different. The levers are first drawn back and 

 the machine placed on the head, and when in the proper position by turn- 

 ing a handle, the levers or pins are all let loose and fit themselves to the 

 shape of the head; they are then locked up in that form and the hat is 

 ironed according to that shape. The French machine being made of ebony, 

 which is a cross-grained wood, the levers warp and swell and the glue 

 does not liold to it long; but I make my levers of mahogany to which the 

 glue holds as strong as the wood itself. Tlie French ebony levers have to 

 be made large and clumsy to have the requisite strength, but as I use ma- 

 hogany, the levers can be made much smaller and therefore a greater num- 

 ber can be put on, giving a more accurate measurement. The price of the 

 machine here exhibited is $50. 



Dr. Rich. — Any one who has had the French machine used on his head 

 will readily see the improvement in this. I have had my head sore for a 

 week from the violence used in pressing the French instrument down on 

 my head. 



A New Wrench. 



Mr. Clark also exhibited a very ingenious instrument for screwing up 

 bolts and nuts when in situations not accessible to the ordinary wrench. 

 It was made in the shape of the letter L, and by turning a small crank at 

 one end a circular wrench was made to turn at the other. It might be 

 called a wrench to act around a corner. 



A New Hay Press. 



Mr. Dederick presented a model of his parallel lever press. He said the 

 screw was the first power used in packing hay, and nothing can be said 

 against it but its slowness. To obviate this the toggle joints is used, 

 which saves some three-fourths of the time in packing a bale of hay. My 

 improvement embraces two levers, as shown in the model here, by which 

 as much power can be obtained as with the screw, and the machine can 

 press eight bales of hay an hour. Probably one half of the hay that comes 

 down the Hudson river is pressed by the toggle joint machine. With hoop 

 iron bands the hay is held best, but it is the most expensive. It is custo- 

 mary to charge one dollar a ton for pressing hay, the owner of the hay 

 furnishing the hoops, bands, &c. 



Mr. Benjamin Garvey. — Several interesting inventions and improvements 

 have been presented to us this evening, and what renders them doubly 

 so is that they are entirely American. In the hay press of Mr. Dederick, 

 we have a very useful application of the lever principle, but there is one 



