Joseph Ketley to Faraday   3 May 1854¹

To Professor Faraday

Providence New Chapel Hs. | Georgetown Demerara | 3rd May 1854

My dear Sir

That which may prove to be of universal consequence in the application of Gutta Percha to works of importance, alone induces me to submit to your notice, the change which has taken place in the elastic properties of Gutta Percha which I purchased from the Company about five years ago. I enclose for your inspection a piece of the same, with their stamp upon it, in order that it might be identified as theirs:- And you will find to your amazement, as I found to my mortification, that it is more brittle than glass! Now if, in five years it has undergone this strange transformation, what might not be the dreadful consequences, if, trusting to its supposed durable qualities, and to its complete adoptation as an effectual and never failing isolator, it should be found that in a few years it should become sufficiently brittle, in the deep, as to suffer the corroding sea water to obtain access to the wires? - and no one be able to account for the sudden failure? - I can but think that this is a matter of serious import. I would have sent this direct to the Company; but felt that it would be preferable first to submit it to your own consideration as being conversant with the substance by having tested & analysed samples for scientific object².

I venture however to state to you my own observations. Two years ago I observed that the Gutta Percha I had by me presented the appearance of a sort of grey oxide, which at first I took to be the effect of a damp atmosphere but upon rubbing it between my thumb & finger found it to be somewhat more substantial than damp:- it was not damp, but dry - & from that moment I began to observe, inasmuch as I had understood that Gutta Percha would not easily decompose & hence was recommended for holding Pure water. After this I had occasion to observe that water (rain water, which here is unmingled with smoke, &c., & is our ordinary drink) standing a few weeks in a Gutta Percha Bucket so far decomposed its surface, as to produce a smooth sort of fungus & to present ropy streaks of what appeared like disintegrated Gutta Percha, in the water. Hence forth I took care never to use the Gutta Percha Carboy for water, nor to drink out of the Gutta Percha Cups which I had bought of the company for travelling purposes.

About 12 months ago, a gentleman brought me about 2 or 3 feet of Gutta Percha Rope or Cord about 1/4 in diameter, which had been recommended for strength - but alas! it was as brittle as sealing wax! - I have kept a portion of it by me - and when a few days since I found how brittle the shoe soles had become I must needs try the said cord - when to my surprize I found it would scarcely bear touching!- I do not know whether the said cord was from Wharf Road or another establishment but I enclose a short piece for your convincing[.]

I cannot tell whether this change is to be attributed to time and these latitudes; or to another cause, which a little further on I will venture to suggest - but in either case I look on it with great concern for the probable future consequences, where it is unsuspectingly confided in, for great works.

Before I suggest the other probable cause I will state further, two things - first some of the Gutta Percha that I have, retains its tough, or elastic property nearly unchanged. I say nearly, because it will bend considerably, but not so elastically that I cannot break it:- which, my impression is, was not the case at first - I have the idea that on certain occasions I tried to break it five years ago and failed - some breaks now more easily than others - some after a scratch with the point of a knife - and some with the slightest touch - for it will not bend at all - has no elasticity whatever.

I cannot but think, my dear Sir, that this should be enquired into; and enquiries be made of a searching kind - because, I repeat it, - because, of possible Consequences.

Having said this much I will now mention to you; that after learning that the wonderful substance called Gutta Percha was the exudation sap of a tree, I set myself in earnest to search after trees yielding milky sap. I found some 3 or 4 or more: and began to think I could recommend a trade in that article from here. One tree in particular yields an abundance of thick jelly like milk every full moon when the sap rises to the extremities - not so at the dark moon. I collected a quantity, and after subjecting it to the bath, somewhat after the manner of the Company, I thought myself prepared to announce the fact - for it appeared tenacious - slightly elastic - and in all respects, or nearly so, seemed to answer the description - Until alas! when it had become thoroughly cold and dry, I found it just as brittle as I now find some of the pieces I bought of the company! Meanwhile I wrote to the Society to ask for a description of the Tree - which I received - but finding my research so disappointing I did not think it worth while to trouble either myself or them any further.

Now then, my dear Sir, for the lesson at least - the probability.

May not the company have been supplied with the brittle saps bearing a resemblance to the true Gutta Percha - somewhat similar to those yielded by our trees here? - May it not have occurred that some of these brittle products have been mixed up in large proportions with the real article & so occasioned the strange result? And might not some of the more brittle substances have been sometimes sent out with little, perhaps sometimes, none of the tenacious Gutta Percha, mingled with it? And in any supposition ought not this thing to be seriously enquired after? For if these spurious sorts have become articles of commerce with the company, then dreadful will be the results! - And if not, then the true article is not safe for great undertakings! - And at some future time - not distant, the telegraphy of the deep will become a terrible failure:- so I sh[oul]d fear.

Allow me however to mention another fact. Yesterday I took a piece of brittle Gutta Percha, to melt the edge of it before a glow of fire in order to rub it on the side of my slipper that had become worse:- and wishing to see whether it would break. To day on taking the same piece in my hand I find that the former elasticity is in some measure restored - but this will not continue[.]

In proof of it I will state another fact. Sometime ago I warmed and rolled into thin flat plates some of the Gutta Percha, with a view to fasten them on the soles of my slippers. I did not so use them - & now those thin pieces are even more brittle than thin amalgamated sheet zinc.

I have by me Gutta Percha tubing and also cord, which has apparently retained its strength except that it will break somewhat easier than I remember to have observed before.

I do not think I need apologize in thus troubling you, if at least I am right in my ideas of the importance of the question. I thank you much for your kind reply to my former query: And hope I may be favoured with your judgment on this matter meanwhile I remain My dear Sir

Yours faithfully | Joseph Ketley

Address: To Professor Faraday | &c &c &c