144 A. DAIGGER & COMPANY, CHICAGO, U S. A. 



2707 FILTER PAPER, Whatman No. 4 (S. & S. No. 604), a soft paper of more open 



texture than the preceding. Extremely rapid, but not re< om- 

 mended for use with the finest precipitates. Especially 

 adapted for the rapid filtration of gelatinous and Jarge par- 

 ticles precipitates such as Ferric Hydroxide and Aluminum 

 Hydroxide; also useful for Pharmaceutical purposes, such as 

 the filtration of fruit juices, syrups, oils, etc. Widely used 

 in Copper and other Ore Mining, Sugar and Cement Labora- 

 tories. 



Diameter, cm 7 9 1112.5 1518.5 24 



Per 100 circles $0.30 .40 .50 .65 .901.302.22 



In sheets 18^4 inches x 22 l / 2 inches, per 100 $ 8.75 



Ditto, per ream 9.90 



2708 FILTER PAPER, Whatman No. 5 (S. & S. No. 602), a very tough, hard paper 



of close texture, that will retain the finest precipitates, such 

 as Barium and Lead Sulphates even when freshly precipi- 

 tated. Especially suited for use with solutions which are 

 filtered with difficulty, and for vacuum filtrations with the 

 Buechner funnel, etc. 



Diameter, cm 7 9 11 12.5 15 



Per 100 circles $0.27 .34 .41 .54 .75 



In sheets, 18J4 inches x 22^ inches, per 100 $ 6.95 



Ditto, per ream 31.50 



2709 FILTER PAPER, Whatman No. 30 (Dreverhoff No. 207; Munktell No. 0), a 



single acid-washed paper of low ash content, rapid and re- 

 tentive. Very satisfactory for the filtration of Ammonium 

 Phospho-Molybdate, Barium Sulphate when properly pre- 

 cipitated, for volumetric Lime determinations and for general 

 quantitative work when the lowest ash is not important. 

 Extensively used in Cement and Metallurgical Laboratories. 



Diameter, cm 7 9 11 12.5 15 18.5 



Ash weight per circle, 



grams 00012 .0002 .0003 .0004 .00057.00087 



Per 100 circles $0.68 .90 1.20 1.50 1.90 2.70 



In sheets, 18^4 inches x 22^ inches, per 100 $21.55 



Ditto, per ream . 97.80 



2710 FILTER PAPER, Whatman No. 31 (Munktell No. OB), a single-acid-washed 



paper similar to No. 30, but more open in texture, making it 

 more rapid. On account of its extreme rapidity it is not 

 recommended for the finest precipitates. Suitable for the 

 very rapid filtration of gelatinous and large particle precipi- 

 tates, for volumetric determinations of Phosphates, for Sili- 

 con in Iron Analysis, and general rapid quantitative separa- 

 tions where the lowest ash weight is not essential. Extens- 

 ively used in Metallurgical Laboratories. 



Diameter, cm 7 9 11 12.5 15 18.5 



Ash weight per circle, 



grams 00012 .0002 .0003 .0004 .00057 .00087 



Per 100 circles $0.68 .90 1.20 1.50 1.90 2.70 



8711 FILTER PAPER, Whatman No. 40 (S. & S. No. 5892, White Ribbon), a double- 

 acid-washed paper of very low ash, all mineral matter having 

 been removed by treatment with hydrochloric and hydro- 

 fluoric acids. Filters rapidly and retains fine precipitates. 

 This is the standard double-washed grade for analytical pur- 

 poses. Excellently suited for Barium Sulphate when prop- 

 erly precipitated and filtered hot, also for Lead Sulphate, and 

 for crystalline precipitates, such as Magnesium-Ammonium 

 Sulphate, etc. 



Diameter, cm 7 9 11 12.5 15 



Ash weight per circle, 



grams 00005 .000082 .00012 .00016 .00023 



Per 100 circles $1.20 1.70 2.00 2.30 2.70 



2712 FILTER PAPER, Whatman No. 41 (S. & S. No. 589, Black ribbon), a double- 

 acid-washed paper similar to No. 40, but more open in texture 

 and therefore filters more rapidly. Suitable for Iron, Alumi- 

 num, and other gelatinous precipitates which can be filtered 

 quickly and washed rapidly and easily. Widely used in deter- 

 mining Silicon in Iron and Steel Analysis. 



Diameter, cm 7 9 11 12.5 15 



Ash weight per circle, 



grams 00005 .000082 .00012 .00016 .00023 



Per 100 circles $1.20 1.70 2.00 2.30 2.70 



