1 64: A. L. Parsons — New Sclerometer. 



.2. The object carrier (0) holds the crystal or other test 

 object firmly in the position desired for making the tests. 

 The crystal is fastened by wax u kit " to a small plate which 

 is set in a socket at the top of the carrier. 



The adjustment of the test object is as follows: 



1. To bring the surface under the test point the transport 

 screw (4) and the screw (1) are used. The screw (1) has also 

 the purpose of moving the test object from side to side so 

 that duplicate measurements may be made in parallel positions. 



2. To give the face of the test object the desired inclination 

 so that it forms with the slide (6) a wedge, it is tilted by means 

 of the screw (2). The inclination will vary according to the 

 hardness of the substance to be tested; very soft substances 

 require only a slight inclination while harder materials require 

 a greater one. This inclination of the surface to be tested is 

 one of the most important features of the instrument, as it 

 gives the measure of the pressure of the spring (F) when the 

 crystal is moved by the transport screw (4). 



3. To level the test object from side to side a screw (3) on 

 the rear of the instrument is employed. 



4. To test the hardness of the substance under investigation 

 in different directions the graduated circle (C) is turned about 

 its axis. This circle is divided into 36 parts so that each division 

 gives 10°. 



3. The transport screw (4) and accompanying spring (5) 

 move the test object under the test point. The inclination of 

 the surface to be tested to the plane of the slide (6) forms a 

 wedge which by the movement of the screw (4) raises the 

 spring (F) until a scratch is made. 



Jf,. The micrometer screw (E) raises or lowers the test object 

 until it just touches the test point. Each division on the screw 

 head measures an elevation of O01 mm . 



5. The base (G-) carries the different parts and needs no 

 particular description. 



Measurement. 



The crystal or other test object is fastened to the top of the 

 object holder (O) and inclined by means of the screw (2) so 

 that the face to be investigated forms a wedge with the track 

 (6). By the screw (3) it is made horizontal from side to side. 

 By raising or lowering the column (S) the test point is brought 

 to a position where it nearly touches the surface to be tested. 

 By means of the micrometer screw the crystal is then raised 

 until the test point just comes in contact with the face to be 

 tested at the point a, fig 2. 



