BAIRD &. TATLOCKL (LOM)ON) LTD. 



I ! Ill 



5084 



5082 5083 



5082 s Sampler for taking samples of water from a depth, with weight and glass tube 



Extra glass tube, exhausted ready for use . . . . . . . . . . per 



5083 Paper Squares, with square black spots printed on, as used for the turbidmetric estimation 

 of magnesia and sulphates in water, as recommended by Dr. Thresh, per doz., 6d. ; per gross 

 5084 s Pair of Tubes on Stand, for comparing the colour of water, with white and mirror glass 

 reflectors 



10 6 

 10 



056 

 2 15 



5085 



5085 Tidy's Tubes for water analysis, glass tubes, with brass screw caps and glass ends. 

 Sizes . . 24 by i 24 by 2 in. 



Price . . . . . . . . 9/6 15/- each. 



i 



i 



5086 



5086 Colorimeter, for testing the colour of water, as devised by \V. T. Burgess, Esq., F.I.C. .. 



(See Analyst, vol. xxvii., No. 319, October, 1902.) 



DESCRIPTION OF BURGESS' COLORIMETER. 



The colorimeter consists of two tubes, each 2 ft. long, placed in a horizontal position, one being filled with 

 the water to be tested (tube A) and the other with distilled water only (tube B) . Light is reflected from an opal glass 

 plate at c, and passes through both tubes. A mirror placed at an angle of 45 degrees reflecting the light upwards, 

 thus enabling the observer to compare the tints of the contained waters at a point about 10 in. above D. By 

 means of a mask no light except that passing through the tubes can be observed. Over the mirror is placed a 

 platform p, with holes supporting two short cylinders E and F. A few cubic centimetres of distilled water are 

 placed in F (which is over tube A), and a standard colour solution is run into E until the depth of colour is the same 

 in both. The amount of standard solution required to be added is recorded in millimetres, and may be read off 

 directly from a scale on the side of E, or by immersing a millimetre rule in the liquid. 



The standard solution contains I gramme pure crystallised cobalt sulphate and 0.05 gramme potassium 

 bichromate per litre. 



350 



CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS. 



