Читать книгу Humphry Davy, Poet and Philosopher - T. E. Thorpe - Страница 7

“Not in the ideal dreams of wild desire

Have I beheld a rapture-wakening form:

My bosom burns with no unhallow’d fire,

Yet is my cheek with rosy blushes warm;

Yet are my eyes with sparkling lustre fill’d;

Yet is my mouth replete with murmuring sound;

Yet are my limbs with inward transports fill’d,

And clad with new-born mightiness around.”

Whether, as the result of this effort, Davy ever again essayed to tempt the muse when under the influence of nitrous oxide is doubtful. Nowadays the gas is too frequently associated with unhappy memories of the dentist’s chair to call up pleasurable associations in a poet’s mind.

Davy concludes his memoir with some cautious speculations as to the mode of action of nitrous oxide. That it acts on the blood he was well aware, but it has been left for subsequent research to determine in what manner. He points out that “as nitrous oxide in its extensive operation appears capable of destroying physical pain, it may probably be used with advantage during surgical operations in which no great effusion of blood takes place.” As is well known, nitrous oxide is now one of the commonest anæsthetic agents.

As regards the general question how far the gases are likely to subserve the interests of medicine, he is very guarded.

“Pneumatic chemistry,” he says, “in its application to medicine is an art in infancy, weak, almost useless, but apparently possessed of capabilities of improvement. To be rendered strong and mature, she must be nourished by facts, strengthened by exercise, and cautiously directed in the application of her powers by rational scepticism.”

Davy’s success with nitrous oxide led him to attempt to respire other gases—such as hydrogen, nitric oxide, carbonic acid—with in one or two cases almost fatal consequences. On one occasion he tried to breathe water-gas, made by passing steam over charcoal, and was with difficulty brought to life again. These deleterious experiments, carried on with all the ardour and impetuosity of his nature, and at the expense of much nervous energy, reacted prejudicially on his health, and he was obliged to seek relaxation and quiet in the pure atmosphere of his native place.

With the approach of winter he was back again in Bristol, with health restored and vigour renewed. The following letter to Mr. Davies Gilbert is interesting as fixing the time at which he entered on the path of inquiry which was to lead him to his greatest triumphs:—

“Pneumatic Institution, Oct. 20, 1800.

“In pursuing experiments on galvanism, during the last two months, I have met with unexpected and unhoped-for success. Some of the new facts on this subject promise to afford instruments capable of destroying the mysterious veil which Nature has thrown over the operations and properties of ethereal fluids.

“Galvanism I have found, by numerous experiments, to be a process purely chemical, and to depend wholly on the oxidation of metallic surfaces, having different degrees of electric conducting power.

“Zinc is incapable of decomposing pure water; and if the zinc plates be kept moist with pure water, the galvanic pile does not act; but zinc is capable of oxidating itself when placed in contact with water, holding in solution either oxygen, atmospheric air, or nitrous or muriatic acid, &c.; and under such circumstances the galvanic phenomena are produced, and their intensity is in proportion to the rapidity with which the zinc is oxidated.

“The galvanic pile only acts for a few minutes, when introduced into hydrogen, nitrogen, or hydrocarbonate [the gas obtained by the action of steam on charcoal]; that is, only as long as the water between its plates holds some oxygen in solution; immerse it for a few moments in water containing air, and it acts again.

“It acts very vividly in oxygen gas, and less so in the atmosphere. When its plates are moistened by marine acid, its action is very powerful, but infinitely more so when nitrous [nitric] acid is employed. Five plates with nitrous [nitric] acid gave sparks equal to those of the common pile. From twenty plates the shock was insupportable.

“I had almost forgotten to mention, that charcoal is a good galvanic exciter, and decomposes water, like the metals, in the pile; but I must stop, without being able to expatiate on the connection which is now obvious between galvanism and some of the phenomena of organic motion....

“I remain with sincere respect and affection, yours

“Humphry Davy.”

To his mother he writes:—

“Hotwells, November 19, 1800.

“My dear Mother,—Had I believed that my silence of six weeks would have given you a moment’s uneasiness, I should have written long ago. But I have been engaged in my favourite pursuit of experimenting, and in endeavouring to amuse two of my friends who have spent some days at the Institute. One of them is your quondam lodger, Gregory Watt, who desired to be kindly remembered to you and the family....

“Accept my affectionate thanks for your presents. I have received them all, and I have made a good use of them all. Several times has a supper on the excellent marinaded pilchards made me recollect former times, when I sat opposite to you, my dear mother, in the little parlour, round the little table eating of the same delicious food, and talking of future unknown things. Little did I then think of my present situation, or of the mode in which I am, and am to be, connected with the world. Little did I then think that I should ever be so long absent from the place of my birth as to feel longings so powerful as those I now feel for visiting it again....

“I shall see with heartfelt pleasure the time approaching when I shall again behold my first home—when I shall endeavour to repay some of the debts of gratitude I owe to you, to the Doctor [Tonkin], and to my aunts. My next visit shall not be so short a one as the last. I will stay with you at least two or three months. You have let half your house. Have you a bed-room reserved for me, and a little room for a laboratory? Which part have you let? When I come to Penzance we will settle all about John; till then I should like for him to learn French and Latin with Mr. Dugart. The expense of this or any other part of his education I will be glad to defray. Do not by any means put him with Mr. Coryton.... I will write to Kitty in the course of next month. I am glad to hear Grace is better....

“All in the way of progress goes on nobly. My health was never better than it has been since I left Cornwall last. I shall be very glad to hear from you soon. You have a hundred objects to write about interesting to me. I can only write of myself.... Love to Kitty, Grace, Betsy and John.

“Farewell, my dear mother. I am your affectionate son

“H. Davy.”

The following letter is to his old friend and benefactor, Mr. John Tonkin:—

“Dowry Square, Clifton, Jan. 12, 1801.

“Respected Sir, ... Natural philosophy has lately been enriched with many curious discoveries, amongst which galvanism, a phenomenon that promises to unfold to us some of the laws of our nature is one of the most important. In medicine, the inoculation for the cow-pox is becoming general, not in England alone, but over the whole of Europe; and taking circumstances as they now stand, it promises gradually to annihilate small-pox. My discoveries relating to the nitrous oxide, the pleasure-producing air, are beginning to make some noise; the experiments have been repeated, with the greatest success, by the professors of the University of Edinburgh, who have taken up the subject with great ardour; and I have received letters of thanks and of praises for my labours from some of the most respectable of the English philosophers. I am sorry to be so much of an egotist; yet I cannot speak of the Pneumatic Institution and its success without speaking of myself. Our patients are becoming daily more numerous, and our Institution, in spite of the political odium attached to its founder, is respected, even in the trading city of Bristol.... I am at this moment very healthy and very happy; I have had great success in my experiments and I gain a competence by my pursuits, at the same time that I am (in hopes at least) doing something towards promoting the public good. If I feel any anxiety, it is that of being removed so far from you, my mother, and my relations and friends. If I was nearer, I would endeavour to be useful to you: I would endeavour to pay some of the debts of gratitude, I owe to you, my first protector and earliest friend. As it is, I must look forward to a futurity that will enable me to do this; but, believe me, wherever I am, and whatever may be my situation, I shall never lose the remembrance of obligations conferred on me, or the sense of gratitude which ought to accompany them.

“I remain, respected Sir, with unfeigned duty and affection, yours

“H. Davy.”