STANDARD GAUGES. 417 



proved, their draught would be lessened, they could 

 be made both lighter and stronger, the parts would 

 not get so quickly loose as they do now, causing the 

 carriage to jolt and shake ; consequently there would 

 not be the noise there is now when a carriage was 

 in motion. 



There are used in the construction of machinery 

 a variety of gauges, some of which might be appli- 

 cable to carriage construction. There are both cylin- 

 drical and flat gauges made for this purpose ; the cylin- 

 drical gauges would be too delicate if made smaller 

 than one-tenth of an inch diameter, so that for sizes 

 below this, down to one-fiftieth, flat gauges are used 

 — a gauge of this form was made by Whitworth. A 

 mechanical means by which the division of very 

 minute quantities can be made visible, was suggested 

 by Mr. Ramsbottom. This is brought about by a 

 corresponding but very noticeable difference taking 

 place in another part of the machine. 



Messrs. Elliot Brothers brought out a pocket-gauge 

 for measuring the thousandth part of an inch. Mr. 

 Holtzapffel also brought out a sliding-gauge for 

 measuring the thousandth part of an inch. Another 

 machine by Sir Joseph Whitworth measures the ten- 

 thousandth ; this has been used for ensuring accuracy 

 in various patterns before issuing them from the pat- 

 tern-makers' shop. Sir Joseph Whitworth also in- 

 vented a machine for computing the millionth part of 

 an inch ; this was exhibited in the Exhibition of 1851. 

 This is, perhaps, greater accuracy than is required for 

 mere carriage-building, but many of the gauges men- 

 tioned would be of great assistance in the making of 

 axle-arms, boxes of wheels, and the screw-nuts by 

 which they are secured to the axle; besides which, too 



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