Faraday report   5 May 1837

I had a piece of sound old sail cloth put into my hands on the 2nd instant for examination¹. I understand it to be sail cloth, which having been prepared by Kyan's process some years ago, had been in constant use since then; and that having worn well it was now desirable to ascertain whether any mercury was present in it as a verification of the understanding that it had been so prepared.

I was not at first able to find mercury in this cloth. Tests were affected as if the metal were present but the action so shewn was referable to the presence of Iron. At last however I satisfactorily proved its presence. The fact is that by long contact with organic matter the bichloride of mercury becomes converted into proto chloride; and also, that by long exposure to rain, weather, &c such part as is not thus rendered insoluble or otherwise insoluble by combination with the fibre, is removed. Hence the metal from diminution of quantity & fixedness of combination is more difficult to trace. My process was to digest a portion of the sail cloth in dilute nitric acid for some time & then to subject the fluid to the action of a voltaic battery using terminations of fine gold: In this way I could separate the metal mercury and distinguish its presence in this particular cloth.

I have lately made some violent experiments on the material action of vegetable fibre and a solution of corrosive sublimate, in order to ascertain whether under any circumstances the latter could injure the former. A small piece of sail cloth about 9 inches square was put into a flask & covered by about a pint of solution of corrosive sublimate (of strength 1 fl [oz] to five gallons water) and boiled daily for three weeks. At the end of that time nearly all the sublimate in the solution had been decomposed and the cloth was found rotten and much injured. I then boiled a similar piece of sail cloth in water for the same time, but did not find that it had sensibly suffered in its strength.

Hence it is evident that at the high temperature applied & by a prolonged contact with a large quantity of the solution the fibre is injured: and therefore it is possible that with certain kinds of cloth some effect may take place in hot climates; although it can be nothing like to the same extent as above, because the proportion of corrosive sublimate applied by Kyan's process is very small. Prolonged experience only can determine whether any effect of this kind does take place and what its amount may be. | M. Faraday

Royal Institution | 5 May 1837