carry on the customary circulation, that the beneficial effects of gestation are felt, but equally so, when comparative inability, arises from redundancy of matter to be propelled. When from fulness of blood, the circulation is obstructed, the whole system labours under a feeling of hurry and agitation, with that sensibility to sudden impressions, which is usually termed nervousness. The mind becomes incapable of any deliberate consideration, and is impressed with horrors that have no foundation, but in a distempered imagination.

It is in moderate degrees of this species of affection, that the advantages of carriage exercise, are most sensibly felt. The composed serenity of mind that succeeds to the previous alarm, is described by some persons, with a degree of satisfaction, that evinces the decided influence of the remedy. With this steadier tone of mind, returns its full power of cool reflection; and if the imagination becomes more alive than usual, its activity is now employed in conceiving scenes that are amusing, and agreeable.

As an instance of direct relief to a circulation, labouring from mere fulness of blood, I may adduce that of a person, whose friends, as well as himself, were apprehensive, from the violent and visible throbbing of his heart, of the existence of some organic mischief, and were in some measure alarmed for the consequences.

He was persuaded, and not reluctantly, to go without delay, for medical advice, and was accordingly conveyed in a carriage to the house of some physician of eminence, but did not succeed in finding him at home. As the symptoms did not appear to admit of delay, and were at least not aggravated by the motion, it was hoped that the wished-for advice might be

obtained at a part of the town, which happened to be at some distance. But the second attempt proved as fruitless as the former, and a third was made with the same event. Since the throbbing had by that time considerably abated, he was contented to postpone any further efforts to the following day, and directed the carriage homewards. By the time that he returned to his friends, he found, that the motion of travelling over several miles of pavement, had apparently removed the complaint. The pulsation of the heart and arteries had subsided to their natural standard, and he congratulated himself, that his search of a remedy had not been ineffectual, although he had been disappointed as to the source from which he thought he had most reason to expect relief.

If vigour can in any instance be directly given, a man may certainly be said to receive it in the most direct mode, when the important service of impelling forward the circulation of his blood is performed for him by external means. The main spring, or first mover of the system, is thereby, as it were, wound up; and although the several subordinate operations, of so complicated a machine, cannot be regulated in detail, by mere external agency, they must each be performed with greater freedom, in consequence of this general supply of

power.

In almost every treatise on the subject of chronical diseases, are to be found numerous instances of the benefit, produced by the several modes of gestation, which have been most generally adopted; as riding on horseback, in carriages, seavoyages, and swinging. And in many cases, which might be adduced, it has appeared too clear, to admit of a doubt, that the cure of the patient, has been owing solely to the external

agitation of his body, which must be allowed, at least, to have had the effect above explained: that of relieving the heart and arteries, from a great part of their exertion in propelling the blood, and may therefore have contributed to the cure, by that means only.

The different modes above mentioned, are adapted from their nature to different degrees of bodily strength, and if there are cases in which, that which appears most eligible, may not suit the situation, or circumstances of the patient, it can not be difficult, to contrive other means of giving motion, so as least to incommode, and yet to give the greatest relief. A very gentle and long continued, or even incessant motion, may suit some cases better than any more violent and occasional agitation; and in this way, probably, it is, that sea voyages have sometimes been attended with remarkable advantage.

II. The Bakerian Lecture for 1809. On some new Electrochemical Researches, on various Objects, particularly the metallic Bodies, from the Alkalies, and Earths, and on some Combinations of Hydrogene. By Humphry Davy, Esq. Sec. R.S. F.R.S.E.

M. R. I. A.

Read November 16, 1809.

I. Introduction.

I HAVE employed no inconsiderable portion of the time that has elapsed, since the last session of the Royal Society, in pursuing the train of experimental enquiries, on the application of Electricity to Chemistry, the commencement and progress of which, this learned Body has done me the honour to publish in their Transactions.

In this communication I shall, as formerly, state the results. I hope they will be found to lead to some views, and applications, not unconnected with the objects of the Bakerian lecture: and though many of them are far from having attained that precision, and distinctness, which I could wish, yet still I flatter myself, that they will afford elucidations of some important and abstruse departments of chemistry, and tend to assist the progress of philosophical truth.

II. Some new Experiments on the Metals from the fixed Alkalies. In the paper, in which I first made known potassium and sodium to the Royal Society, I ventured to consider these

bodies according to the present state of our knowledge, as undecompounded, and potash and soda as metallic oxides, capable of being decomposed and recomposed, like other bodies of this class, and with similar phænomena.

Since that time, various repetitions of the most obvious of the experiments on this subject, have been made in different parts of Europe. The generality of enlightened chemists, have expressed themselves satisfied both with the experiments, and the conclusions drawn from them: but as usually happens in a state of activity in science, and when the objects of enquiry are new, and removed from the common order of facts, some enquirers have given hypothetical explanations of the phænomena, different from those I adopted.

MM. GAY LUSSAC and THENARD, as I have mentioned on a former occasion, suppose potassium and sodium to be compounds of potash and soda, with hydrogene; a similar opinion seems to be entertained by M. RITTER. M. CURADAU* affects to consider them as combinations of charcoal, or of charcoal and hydrogene, with the alkalies; and an Enquirer in our own country, regards them as composed of oxygene and hydrogene.

I shall examine such of those notions only, as have been connected with experiments, and I shall not occupy the time of the Society with any criticisms on matters of mere speculation.

In my two last communications, I have given an account of various experiments on the action of potassium upon ammonia, the process from which MM. GAY LUSSAC and THENARD, derive their inferences. At the time that these papers were Journal de Physique June, 1808. + Nicholson's Journal. August, 1809. p. 258. MDCCCX.

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