6 Supplevient to the Value of increasing Life Annuities. 



what extent these substances existed, with a view to ascertain 

 the safest strength of alkaline applications to be vised in the 

 different processes of bleaching. Alkalies are the common sol- 

 vents used by bleachers ; but I did not conceive them altogether 

 adapted to my present purpose. I took alcohol, and succeeded in 

 bleaching to a very beautiful whiteness flax in its unripe state 

 and in its early stages; but as the flax ripened, its power lessened. 

 I exposed full ripe flax to the action of alcohol, both in a liquid 

 state and in the state of vapour, till I satisfied myself of having 

 extracted all the resinous matter; — still a colour remained. I 

 subjected it to the action of an oxymuriate, and was astonished to 

 see the presence of iron so strongly indicated. I took another 

 quantity of this full ripe flax, and boiled it in a lev of prussiate of 

 potash, prepared bv calcination of common potash with green 

 whins: from this it was washed, and immersed in oxymuriate of 

 lime, which produced a beautiful light bhie. This experiment 

 I repeated till I produced, by ai)parenth the same process, on 

 the unripe flax a beautiful white, and on the full ripe a fine, full, 

 Prussian blue. This explained in a most satisfactory manner 

 manv of the phsenomeua of bleaching I never before could com- 

 prehend, and appeared to me a most wonderful work in nature, — 

 the formation of a metal in the juices of a plant, whose ex- 

 istence was not detected, bv the same means, in the same plant, 

 only fourteen to twenty days younger than where its presence 

 became so manifest. 



Tan also exists in flax, and is very soluble in water 

 In steeping flax, the water in the pond becomes impregnated 

 with tan. '^''he process of fermentation comes on, in the pro- 

 gress of which the iron is acted upon. The iron and tan corn- 

 bine, precipitate, and form an almost indestructible dye. 



Thus, by inattention to the steeping of flax, the labour and 

 expense of bleaching are greatly increased. The linen loses much 

 of its strength and durability by the necessary process of bleach- 

 ing, and destroying a colour which, by due care, might be pre- 

 vented from ever fixing itself. With esteem, I remain. 



Dear sir, yours sincerely, 

 Strathendrv BleachfieW, GaviN InGLIS. 



Dec. iO, 1817. 



II. Supplement to Mr. Bunwell's Paper on the f'nlue of in- 

 creasiicg Life Aunuiiies, in our Number fur September 1817. 



To Mr. Tillock. 



Sir, — £ rom the circumstance of having changed the original 

 form of the theorems for determining the values of increasing 



life 



