56 REPORT—1874. 
This dissociation by sunlight is due to the violet end of the spectrum, the red end 
having no effect whatever. 
Liquid nitrous acid, obtained by condensing the gas derived from the action of 
arsenious acid on nitric acid and exposing it in a strong sealed tube, is not decom- 
posed. 
On a Mode of producing Spectra on a Screen with the Oxyhydrogen Flame. 
By P. Branam, FCS. 
On the Mode of writing Chemical Equations. 
By Professor Crum Brown, F.R.S.LZ. 
On Methyl-thetine*. By Prof. Crum Brown and Dr. E. A. Lerrs. 
On. the Replacement of Organic Matter by Siliceous Deposits in the Process of 
Fossiizution. By Dr. W. B. Carventer, PRS. 
The Injurious Effects of Dew-rotting Flaw in certain cases. 
By Wii11am Cuartry, J.P., of Seymour Hill, near Belfast. 
The cultivation of the flax-plant in the field is not a matter of extraordinary 
difficulty. It is the after-management that generally embarrasses the farmer, and 
particularly in those districts where the crop is tried for the first time. The extension 
of flax-cultivation in the British Isles would be very useful to the important 
industry of the linen manufacture, and would add a remunerative crop to the 
limited list of the British agriculturist. At present the land occupied by flax is 
chiefly to be found in Ulster. The present year’s return gives 102,789 acres for this 
province, the rest of Ireland showing only 4097 acres. The author is not aware 
of any accurate statistics on the subject regarding England and Scotland, but a few 
thousands would probably cover the quantity of acres cultivated. 
The first difficulty that meets the inexperienced farmer after his flax is gathered 
off the field is the steeping-process. The celebrated Louis Crommelin (appointed 
overseer of the linen manufacture in Ireland by King William III.), writing in 
1705 on the subject of preparing flax, quaintly says :—‘“ Flax may be prepared 
without watering by grassing it until such time as the stem corrupts; yet it is 
better to water it where it can possibly be done without great inconvenience.” 
So far as the author can form an opinion, this plan of preparing without watering, 
commonly called “dew-rotting,” is quite unsuited for any but the coarsest flax, 
such as would not be spun into yarn used for making bleaching cloth. There is 
something in the process of steeping flax (a process more accurately, perhaps, 
described by the common expression of retting or rotting) which seems necessary 
to ensure the attainment of high colour when the prepared fibre is manufactured 
into cloth, and arrives at the bleaching department. The fermentation, which seems 
to be of a putrefactive nature, acts on the juices and gummy matters which cement 
the woody stem to the pure fibre of the plant, and also not only assists the after 
separation of these, which is the object of the subsequent scutching-operation, but 
has such a powerful effect on the colouring-matter of the fibre as to render the 
change required in bleaching much more safe and successful. But though grassing 
alone is not sufficient to make a proper preparation of good fibre, it is, after the 
steaping is over, a most useful and necessary addition. 
There is another point worth mentioning in connexion with the steeping of flax; 
brackish water, such as may be met with in the low-lying districts near the sea, should 
be carefully avoided. The practice of using it is now generally admitted to be 
iajurious to the fibre intended for white linen; it also gives a leaden dull colour 
* Published in ‘ Nature,’ vol. x. p. 389 (Sept. 10, 1874). 
