AL-KENNA 89 



carbonate, which has escaped, and from which, of course, the quantity of the car- 

 bonated alkali acted upon may be calculated. Suppose in effect, that the loss is 19 

 grains : taking the 



Equivalent of soda . . . 4 , . . =31 

 do carbonic acid . . . . .=22 



1 equivalent of carbonate of soda . . . = 53, 



it is clear that the 19 grains of carbonic acid which have been expelled represent 

 4577 grains of carbonate of soda, or, in other words, 100 grains of soda ash operated 

 upon contained 4577 of real carbonate of soda, thus : 



CO* NaO.CO 1 CO* NaO. CO 2 



22 : 53 :: 19 : x = 4677 



95. As the soda ash of commerce always contains earthy carbonates, and very fre- 

 quently sulphurets, sulphites, and occasionally hyposulphites, instead of putting the 

 100 grains to be operated upon directly into the flask A, it is absolutely necessary 

 first to dissolve them in boiling water, to filter the solution, and to wash the precipi- 

 tate which may be left on the filter with boiling water. The solution and the wash- 

 ings being mixed together, should then be reduced by evaporation to a proper volume 

 for 'introduction into the flask A, and the process is then carried on as described. If 

 sulphurets, sulphites, or hyposulphites are present, the ash should be treated exactly 

 as mentioned in 83-91, previous to pouring the solution into the flask A, since 

 otherwise the sulphuretted hydrogen and sulphurous acid, which would be disengaged 

 along with the carbonic acid, would apparently augment the proportion of the latter, 

 and render the result quite erroneous. 



96. The balance used for this mode of analysis should be capable of indicating 

 small weights when heavily laden. 



AXiKAXiXVTE EARTHS BAKYTA, LIME, and STEONTIA. These earths are so 

 called to distinguish them from the earths MAGNESIA and AXUMINA. They are soluble 

 in water, but to a much less extent than the alkalies. Their solutions impart a brown 

 colour to turmeric paper, and neutralise acids. They are, however, distinguished 

 from the alkalies, by their combination with carbonic acid being nearly insoluble in 

 water. 



AIiKAXiI WASTE. A by-product obtained in the manufacture of soda-ash. 

 By heating sulphate of soda with chalk and carbonaceous matter, a mixture of car- 

 bonate of soda and sulphide of calcium is obtained. The former salt is dissolved out 

 on lixiviation, whilst the latter remains as an insoluble residue. It is this residue 

 which constitutes ' alkali waste.' The accumulation of this material is aften a source 

 of great annoyance to the manufacturer, especially by the evolution of sulphuretted 

 hydrogen. Several methods have, of late years, been introduced for the utilisation of 

 this product, and the recovery of the sulphur which it contains. For a description of 

 these processes see SODA. 



AIiXANET. ( Orcanette, Er. ; Orkanet, Ger.) AncJiusa tinctoria. A species of 

 bugloss, or boragewort, cultivated in the neighbourhood of Montpellier and in the 

 Levant. It is sometimes called the bugioss of Languedoc, or the dyer's bugloss. 

 The anchusa is a rough plant, with downy and spear-shaped leaves, and clusters of 

 small purple or reddish flowers, the stamens of which are shorter than the corolla. 

 It affords a fine red colour to alcohol and oils, but a dirty red to water. Its principal 

 use is for colouring ointments, oils, and pomades. The spirituous tincture gives to 

 white marble a beautiful deep stain ; but, usually, wax is coloured with the anchusa, 

 and then applied to the surface of warm marble. It stains it flesh-colour, and the 

 stain sinks deep into the stone. Oil coloured by alkanet is used for staining wood in 

 imitation of rosewood. 



Alkanet root was analysed by Dr. John, who found the constituents to be a peculiar 

 colouring matter (pseudo-alkanium), 5'50 ; extractive, TOO; gum, 6 '25; matters 

 extracted by caustic potash, 65'00 ; woody fibre, IS'OO. 



The colouring matter resides in the cortical part of the root, and was regarded by 

 Pelletier as a kind of fatty acid (anchusic acid) ; but it is now usually considered to 

 be a resinoid (anchtisine), whose composition is C 3i H 20 O 8 (C ss K 40 O"). This root is 

 sometimes termed the spurious alkanet root (radix alkannce spurite), to distinguish it 

 from the Al-kenna. 



AXi-KEXrarA, or AXi-HENNA, is the name of the roots and leaves of Lawsonia 

 inermis, which have been long employed in the East to dye the nails, teeth, hair, 

 garments, &c. The leaves, ground and mixed with a little limewater, serve for 

 dyeing the, tails of horses in Persia and Turkey. 



