122 [Assembly 



equally fitted from its nature, to act sensibly under a burden of many 

 tons: its quality comparing with that of the air spring while it is 

 less liable to get out of order. 



The question of durability suggests itself as one of importance to 

 be considered: the adhesive qualities of India rubber seem to guard 

 against all fear of a fracture, for the particles of rubber are made to 

 cohere by pressure; and as this spring acts by pressure instead of 

 tension, the question is theoretically settled as to their durability; 

 but the practical experience of continued and hard use for six or 

 eight months was an evidence before the committee, and was the 

 ground of unqualified belief in its durability. 



The India rubber employed in the construction of this truck, and 

 for the insulating belt of the cushion wheel, is of the kind known in 

 the United States as " Goodyear's prepared India rubber," and in 

 England by the name of " Vulcanized India Rubber," and has the 

 qualit}' of not being affected by heat or cold, and is therefore highly 

 adapted to the purpose; or rather without this quality, the spring 

 would be worthless. 



But there arfe other considerations proper to notice in this place; 

 it has been ascertained, that railroad axles, after running some 

 70,000 miles become greatly depreciated in their quality; that the 

 particles of iron become crystaiized or changed from a fine firm 

 texture to that of a coarse and brittle character, and therefore are 

 liable to fracture; that this change is due, either to concussion or to 

 currents of electricity. If the former is the cause, the cushion 

 greatly modifies the blow and nearly abates the cause; and if the 

 latter is the cause, the insulating belt entirely intercepts the currents 

 between the road track and the axle; the india rubber being a non- 

 conductor of electricity; but your committee venture no opinion as 

 to results growing out of this consideration — the theory is plausible. 



The rim part of this wheel can be withdrawn when worn out 

 without being at an additional expense of the hub part, which is to 

 remain a permanent fixture and makes strongly in favor of this 

 wheel. No objection to this truck exists in point of cost or weight, 

 and the same commends itself to the consideration of railroad com- 

 panies and truck builders as being a desirable article, whether for 

 freight or passenger cars, particularly for the list named. 



Improvement in Blooming Forges — Making iron direct from ore. 



A model of an improved forge with specimens of iron was exhi- 

 bited at the late Fair by Alexander Dickerson of New-Jersey. 



