ox THE ACTION OF LIGHT UPON DYED COLOURS. 293 



Oxyketone Colours. 



Mordant Colours * Alizarin Black SW (Cr) (Fe). Sodium bisulphite compound of 

 dioxy-naphthoquinone. S. and J. III. 385. 

 „ * Alizarin Bordeaux G (Fe). Constitution not published. 



„ * Alizarin Bordeaux B (Fe). Tetra-oxy-anthraquinone (1.2.5.8). 



Quinalizarin. S. & J. III. 403. 



Class V. Very Fast Colours. (Wool.) 



Oxyketone Colours, 



Wool Book XIV. 



Jlordant Colours Alizarin Bordeaux GG (Fe). Constitution not published. 



Silk Patterns. 



Most of the foregoing colours were also dyed on silk, and the patterns 

 were exposed to light along with the woollen patterns. The relative 

 fastness of the various colours is generally the same as on wool, and a 

 special classification for silk seems unnecessary. 



The Carhohydrates of the Cereal Straws. — Third Report of the Com- 

 mittee, consisting of Professor E. Waeington {Chairman), Mr. 

 Manning Prentice, and Mr. C. F. Cross (Secretary). {Brawn 

 up by Mr. Cross.) 



The work, which was carried out in the agricultural season of 1897, has 

 been reported upon in a paper published in the ' Journal of the Chem. 

 Soc' 1898, p. 4.59. The purpose of these later investigations was to 

 trace the effect of removing the seed-bearing organs upon the carbo- 

 hydrates of the stem. The results were, however, negative, adding 

 another confirmation to the conclusion previously arrived at, that the 

 carbohydrates of the stem tissues are built up with a constant ratio of 

 ' furfural-yielding ' to normal hexose carbohydrates. Further evidence 

 was also obtained that these two groups of carbohydrates are in the earlier 

 stages of growth similarly attacked by boiling dilute acids, and after such 

 hydrolysis are similarly fermented by yeast. 



It must in fact be admitted that as condensation to furfural is by no 

 means an exclusive characteristic of Cj Carbohydrates, there is no evidence 

 whatever that the furfuroids of the barley straw are, in the early stages of 

 growth, pentose-anhydrides or pentosanes. 



There now appears in the ' Journ. Fed. Inst.' Brewing, 1898, p. 438, 

 an article by Tollens under the title ' On the Carbohydrates of Barley and 

 Malt, with special reference to the Pentosanes,' in which, as a result of 

 yeast fermentations of the products of acid hydrolysis of brewers' grains, 

 the author arrives at the following conclusions : — ' From the behaviour of 

 these furfural-yielding substances on fermentation we are forced to the 

 view that they behave, to some extent, similarly to the ordinary hexoses, 

 and somewhat diSerent from the pentoses, for when brought into contact 

 with yeast they exhibit certain manifestations of fermentation ; but they 

 give rise to the formation of but little alcohol and much acid. It must be 

 concluded from this that the furfural-yielding substances . . . contain a 

 certain amount of other substances more susceptible to fermentation than 

 arabinose and xylose. They may contain glycuronic acid or oxycellu- 

 loses. . . .' 



We are very glad to have this confirmation from so great an authority 



