Criticism of Davy
How was Davy criticised and how did he respond to criticism?
Davy was asked in January 1823 by the Admiralty to find a way to prevent the corrosion occurring on the copper bottoms of ships. He very confidently assured the Admiralty and Navy Board that he had found a certain method – the fitting of zinc or cast iron protectors, which became known as ‘Davy’s protectors’. Unfortunately, what had worked in the laboratory did not work at sea and the electro-plating had a chemical side-effect, which provided nutrients for weeds and barnacles, and resulted in ships’ bottoms being fouled thus slowing them down considerably.
The letters below were written at the time, one criticising Davy and then Davy’s reply to this criticism.
- What do you think of the tone of these letters?
Read this criticism of Davy’s protectors in The Times, 16 October 1824, p. 2:
‘Preservation of Ships’ Copper. — It is well known that the copper lately employed to sheath ships belonging to the Royal Navy or to private traders has been liable to rapid oxidation and decay. It was of the utmost importance to ascertain the cause, and to discover the remedy of this acknowledged evil. At one time it was thought the copper was more liable to be acted upon by the salt water on account of its mixture with other metals. It was accordingly purified from alloy; but it was not rendered more durable. After many trials, a mixture of copper with another metal was formed, which had the property of longer resisting sea-water; and a patent was taken out for it by Mr. Mushett, of His Majesty’s Mint. This gentleman was employed by the Lords of the Admiralty to try some experiments with his patent copper; and accordingly proceeded to Portsmouth, where he saw some ships’ bottoms sheathed half with his and half with the common copper. So far as the durability of the metal can be judged of from its state of preservation, this experiment has succeeded. But in the mean time, their Lordships had called in the assistance of Sir H. Davy, the President of the Royal Society, at the head of a committee of that body. This eminent chymist ascertained that copper might be preserved from corrosion by sea-water, through the means of galvanic action, by attaching knobs or pieces of iron to the sheathing metal. He accordingly provided several ships with preservers of this kind, and the experiment so far succeeded as to protect the copper from decay; but it has been found out, that vessels coppered on this plan have returned after short voyages perfectly foul — their bottoms covered with sea-weeds, barnacles, or other worms. The remedy, therefore, is worse than the disease. The oxidation of the metal is prevented by the defensive action of the iron; but the animalculae which this oxidation used to destroy, prey in security upon the vessel when so defended by such durable copper. The learned President’s experiments may, therefore, be regarded as a failure, so far as advantage to navigation is concerned, however useful they may be to chymical science, and however pleasant they may have been to himself in procuring a summer excursion, at the public expense, to the North Sea and the Baltic.’
The following (including Davy’s reply) was published in The Times, 18 October 1824, p. 3:
‘Sir H. Davy and Copper Bottoms.
We insert, with a feeling of great regret for the author, but with no feeling of reluctance on our own account, the following very singular letter from the President of the Royal Society, in answer to a paragraph which appeared in our paper of Saturday [i.e. the article above]. If the passion of the learned President had not entirely blinded his understanding, he must have seen that the language which he employs is neither becoming the chair which he occupies, nor calculated to produce conviction in the quarter which he addresses. In order to have the pleasure of making out as many assertions as possible to which he may apply the epithet of “false,” he divides our paragraph into five propositions, which he takes the liberty of contradicting, and only one of which touches the point at issue between us and the learned President.
First, that a committee was appointed to investigate the causes of the rapid decay of copper-sheathing, Sir Humphry does not deny; though, claiming to be at the birth of the said committee, he corrects us with respect to its genealogy, and ascribes its origin, not to the Admiralty directly, but to the Council, through the representation of the Admiralty. We give the learned President all the benefit of this distinction, and would only beg to ask him, in return, as the price of our concession, how many meetings of this Council-sprung committee he himself attended? The second assertion which he draws from our paragraph for the purpose of contradicting, is the only proposition respecting which we are at issue with the learned President. If ships protected by his principles have neither got foul when sent on short voyages, or retained in harbour, then our information was wrong; but even though it were correct, as we still believe it to be, we would not apply the word false to the President’s contradiction, without a stronger provocation than that which he received. Our answer to his second head of charge will apply equally to the third. With regard to the President’s fourth declaration of “untruth,” we shall say nothing. It would disgrace a child to enter into discussion with him on the point. Did he or did he not pay for his voyage in the Steam-boat? If he did not, did he not sail at the public expense? But the last contradiction of the learned President, probably appeared to him the most overpowering. We presumed, without inspecting the log-book of the steam-boat, that the President had as “pleasant a voyage” as all philosophical inquirers ought to have on so laudable an expedition. When, lo and behold, we are informed that we were again in error — that the passage was stormy, and the President sea-sick. Having no object but truth in any of our statements, we only wish the head of the Royal Society a better voyage, and a better temper, the next time he sails on a philosophical cruise.
To the Editor of the Times
Having seen my name in The Times connected with ‘copper sheathing and patent copper,’ I think it right to inform you that every thing relating to me in that paragraph is false.
You probably will not wish statements which are erroneous, which some may think calumnious, and which may mislead the ship-owners of the country, to be noticed any where but in your own pages. I trust, therefore, that you will insert an immediate contradiction of them in your paper.
I am, Sir,
It is not true that any committee of the Royal Society was formed to investigate the causes of the decay of copper sheeting, at the request of the Lords of the Admiralty. The Commissioners of the Navy Board consulted with the President of the Royal Society on this subject, and he proposed to them to refer it to the Council, who formed a committee for the investigation of it. This was in 1822, long before ‘patent copper’ was heard of.
It is false that any vessels, protected according to Sir H. Davy’s principles, and sent out upon short cruises by the Lords of the Admiralty, have returned infested with worms and barnacles.
It is false that any failure has taken place in my experiments. As far as they have yet gone, they seem to show that the decay of copper may be entirely prevented in harbour, and to a great extent in sailing, by the protectors; and the ravages of worms, &c., upon protected ships, is an entire fiction: indeed, it requires peculiar ingenuity to imagine how worms can prey upon the bottom of a ship, the copper of which remains untouched.
It is not true that the President of the Royal Society has made any voyages at the public expense. The Commissioners of Longitude having resolved to ascertain the longitude of different points of great importance to navigation in the North Sea, by chronometers, the use of the Comet steam-boat was granted to them by the Admiralty, and she was put under the direction of the President of the Royal Society for this purpose, and he took the opportunity of trying certain experiments on the protection of copper, going in her to Sweden, and coming back in her from the north of the Weser, making his journeys and voyages in Sweden, Denmark, Holstein, and Hanover at his private expense.
It is not true that he had a pleasant voyage. He had a stormy passage out, and a still more stormy passage home; and he wishes the author of the paragraph in question no severer punishment for his inaccuracies and ill-will, if he be a landsman and liable to sea-sickness, than a similar voyage.
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