BAIRD ^TATLOCK (LONDON) LTD. 



5021 5023 



5021 s Vacuum Jacketed Glass Tubes as used in Hehner's bromine test for oils. Price without 



platinum wire. Size 4 by i in. inside . . . . . . t . . . each 



5022 s Thermometer for above, 10 to 75 C., in fifths 



(See article by Mr. L. Archbutt, F.I.C., Journal of the Society of Chemical Industry, April, 



l8 97. P- 309-) 

 5023 s Apparatus for Testing the Viscosity of Glue, by Weiss 



029 

 040 



11 5 



5024 



5024 s Wilson's Chromometer, for determining the colour of petroleum Price, with four 

 standard glasses, Nos. i, 5, 10, 15, as below 



No. i = Water white. 

 5=Superfine white. 

 io=Prime white. 

 i5=Standard white. 



If required, additional glasses can be supplied between Nos. 5 and 10, marked 6, 7, 8, 9, and between Nos. 10 

 and 15, marked n, 12, 13, 14, at the extra price of 12/6 per glass. 



This instrument consists of two similar tubes, 16 in. in length, closed at each end by a screw cap carrying 

 a stout glass disc. Light is reflected upwards through the tubes by a mirror, and is then by two pairs of prisms 

 twice reflected, and thus brought into an eyepiece. One of the tubes is filled with the oil to be tested, and beneath 

 the other, which is empty, a disc of stained glass is placed. On looking through the eyepiece, the field is seen to 

 be divided by a sharp line formed at the juncture of the two pairs of prisms, the two halves of the field being 

 tinted respectively with the colour of the oil and that of the standard. An accurate comparison can thus be made. 

 The four standards representing the various grades of colour recognised commercially are prepared from Mr. 

 Robert Redwood's standards. (See pp. 546, 547, vol. ii., Petroleum, by Sir Boverton Redwood.) 



6 10 



CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS- 



