Blue lances

It is therefore obvious that the blue lance (in common with other systems) is temperature-dependent. In order to produce a good blue, the temperature must be controlled to ensure that the largest possible amount of vaporised CuCl is present in the flame. A typical spectrum contains wavelength peaks in the region 420-500 nm attributable to CuCl band spectra, a peak at 770 nm due to atomic potassium from the oxidiser, together with CuOH band spectra between 535 and 555 nm. 

Other coloured flames follow similar physico-chemical phenomena but operate in different regions of the spectrum. Consequently, the maker of the coloured lance has at his disposal copper salts for blue, strontium salts for red, sodium salts for yellow and barium salts for green, as shown in Table 10.2. 

Composition for lances. Yellow saltpeter 16 parts, meal powder 16, sulfur 4, amber 4, and colophony 3 parts. Rose saltpeter 16 parts, lampblack 1, meal powder 3. White saltpeter 16 parts, sulfur 8, meal powder 4. Blue saltpeter 16 parts, antimony (sulfide) 8, very fine zinc filings 4. Green saltpeter 16 parts, sulfur 6, verdigris 16, and antimony (sulfide) 6 parts. 

Features A strong, straight, square stem reaches eighteen inches in height, and heart- or lance-shaped, tooth-edged leaves grow opposite each other on a short stalk. The pale blue flowers, with a helmet-shaped upper lip, bloom in pairs just above the leaves. Both taste and odour are feeble. 

The name "saw" palmetto comes from the sharp-edged fan-shaped leaves. The bladelike serrated edges create nearly impenetrable thickets. The leaves are palmate (fan-shaped) and are divided into 18 to 24 lance-shaped leaflets. The leaves range in color from blue-green to yellow-green to an almost silvery white. The aromatic flowers are an ivory-white color and are found in large clusters. May through July. 

John Mercer (Dean or Great Harwood, nr. Bolton, Lancs., 21 February 1791-Oakenshaw, Lancs., 30 November 1866), a calico-printer, discovered mercerising (1844), the use of potassium ferrocyanide and potash for the discharge of indigo (1848), the use of arsenates as a substitute for phosphates in dunging the manufacture of sodium stannite and stannate, stannous sulphate from tin and copper sulphate solution, Turkey-red oil, the solubility of cellulose in ammoniacal copper solution, and blue-print photography. He taught himself chemistry from a second-hand copy of the Chemical Pocket-Book of James Parkinson, of Hoxton Square, London (2 ed. 1801, 3 ed. 1803). ... 

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