long enough in vacuo, to disengage the air with which it is mixed. The consequence is, that it is liable to become liberated, and, of course, interferes with the results. The original directions of the inventor have also been departed from, as to the proportions of the different parts, and as to the construction of the indices. Those upon Rutherford's plan are universally sealed with air in their upper parts, which acts as a spring against the expansion of the column: the iron index of one is liable thereby to become oxidated, and adheres to the glass when the mercury passes it, and it becomes entangled; while the spirit of the other being unavoidably mixed with air, when the pressure is decreased by cold it is disengaged. The air may be again dissolved by increasing the pressure before a fire, and passing the bubble backwards and forwards, and, in a state of solution it does not appear to interfere with the equability of the expansion. This, however, is not certain; and, at all events, it is liable to re-appear, and is very troublesome. These imperfections are by no means necessary consequences of the construction of the instruments, although the makers are very willing that they should be so considered; but it requires great care and attention to guard against them. The general mounting of the meteorological thermometers is exceptionable in every way; buried as they are in a thick mass of wood, and covered with a clumsy guard of brass, they can but very slowly follow the impression of atmospheric temperature. The establishment of a perfect standard thermometer, which shall be accessible to all who may wish to consult it, will also, doubtless, be another object of the Committee of the Royal Society." P. 368.

Attention to the perfection of instruments, however, as the author has very correctly observed, will be all in vain, without a proper degree of care and system in making and recording the observations. The proper hours of the day for observation are indicated by the barometer: the maximum height of the mercurial column is at about nine A. M., the mean at twelve, and the minimum at three P. M. Where an individual has time to make three observations in the day, these hours should be preferred; if he can only observe twice, the first and last hours should be the periods; and if only once, noon should be the time. Even those who merely consult the barometer as a weather-glass, would, Mr. Daniell asserts, find it an advantage to attend to those hours; for he has remarked that much the safest prognostications from this instrument may be derived from observing when the mercury is inclined to move contrary to its periodical course. If the column rise between nine A. M. and three P. M., it indicates fine weather; if it fall from three to nine, rain may be expected.

The thermometer should be inspected at the same periods, in addition to which the author recommends that the maximum and minimum, by register thermometers, should be carefully noted; the instruments should, of course, be sheltered from every kind of radiation.

The periods of the barometric observation are recommended also for those of the hygrometer; the mean pressure of the aqueous atmosphere, however, being calculated from the dew-point at three P. M., and the lowest temperature at night of the sheltered thermometer.

This Essay comprises also some interesting information on the change in the freezing point which occurs in time in the best thermometers, and has been imagined to be owing to the alteration of form and capacity which the glass undergoes from the pressure of the atmosphere upon the vacuum of the tube; as well as some remarks upon the correction to be applied to barometers for the expansion of mercury and mean dilatation of glass. For information on these points the reader is referred to the Essay itself.

Independently of the Essays to which we have already adverted, there are several others of very considerable interest to the philosopher contained in the volume before us; of these our limits will only admit of an enumeration of the titles; they will be found, however, not less scientific and important than those on which we have dwelt at some length. They are,-1. An Essay upon the radiation of heat in the atmosphere. 2. An Essay upon the horary oscillations of the barometer. 3. Meteorological observations at Madeira, Sierra Leone, Jamaica, and other stations between the Tropics, by Captain E. Sabine, R.A. F.R.S. 4. Meteorological observations in Brazil, and in the Equator, by Alexander Caldeleugh, Esq. And 5. Meteorological observations upon heights. The work is also concluded by an excellent meteorological journal for three years, commencing on the first of September, 1819.

After the analysis and extracts which we have given in the preceding pages, it is almost unnecessary for us to remark on the mode in which the work is executed. The various subjects, it will have been observed, are treated of in a manner highly creditable to the talents and scientific acquirements of the author; whilst the language is in general elegant and perspicuous; the reasoning forcible; and the propositions, drawn from principles premised, are logical. To the lover of meteorological science in particular, as well as of natural philosophy in general, these Essays will be found to form a rich mine of new and important information.

II. A Translation of the Pharmacopeia of the Royal College of Physicians of London, 1824. With Notes and Illustrations. By Richard Phillips, F.R.S. L. and E. &c., &c.

Considering the materials he has had to work upon, Mr. Phillips has really given us a very useful book, in his translation, as he calls it, of the Pharmacopæia; and has shown something of alchemical power, in respect to the contents of the meagre original. We are well aware of the talents that exist in the College of Physicians, and are therefore utterly at a loss to account for the careless imbecility of the productions which are, from time to time, sent forth under its auspices. Where is Dr. Wollaston? where Dr. Young? What has become of Dr. Maton and Dr. Paris? have they no interest in the public character of the body which they adorn; or are they merely careless of its reputation; or do they leave so weighty a concern as the publication of the Pharmacopoeia to the beadle and the bookseller? These are questions asked every day, and every where, and we profess our entire inability to offer to them any plausible reply. That they are not unjustly asked, we are sorry to say is but too manifest, from the present edition, which we understand to be the production of a Committee of the College; and although some tendency towards improvement is manifest in several of the processes, the general execution of the work is very unworthy of its

source.

The old preface of the edition of 1809 is unaccountably reprinted, and attached to the present work; had this preface contained a history of pharmacy, or a review of former pharmacopoeias, its retention might have been excusable; but it is, in fact, a poor and empty production, and particularly inappropriate to the present state of pharmaceutical science, which has lately made such rapid and important progress. To illustrate and expound this progress should have been the business of the preface, if any were thought necessary. The researches which have led us to a tolerably accurate knowledge of the substance upon which the activity of opium depends, and those which have taught us the existence of distinct salifiable bases in the greater number of narcotic vegetables; the inquiries instituted with so much success respecting the principles upon which the active powers of the varieties of Cinchona depend; and those which have taught us the importance of iodine, and some of its combinations, in the treatment of glandular diseases; all these subjects should have been touched upon in the preface, if preface there needs must be ; we ought also to have been informed why the college have not introduced any of these new and active substances; whether they consider them ineffectual, or dangerously active; why they have altogether passed them by; why they have retained in the list of their Materia Medica, sorrel and wood-sorrel, marsh-mallow and coltsfoot, bistort and cuckoo-flowers, centaury, contrayerva and cowVOL. XVII. 2 B

hage, carrots, raisins and figs, bay-berrics and mulberries, opoponax and sagapenum, storax, oyster-shells and toxicodendron; why, in short, so much of the old lumber is suffered to encumber this new work, while so many useful novelties, which have a place in foreign pharmacopoeias, are omitted. We are fully aware of the mischief and absurdity of stuffing every new crudity into a pharmacopoeia; the Parisian codex amply proves that; but when we know that all apothecaries are obliged to keep sulphate of quinina and hydriodate of potash, and acetate of morphia, and that several Fellows of the College, justly eminent for their skill and extensive practice, prescribe and have faith in these compounds, there are, we think, grounds for the questions we have humbly submitted. Our experience, however, obliges us to admit that there must be some hidden obstacles and unseen difficulties in the way of compiling a good and rational pharmacopoeia; for, taking it all in all, that of the London college is perhaps the best extant. Whether to the prevalence of a pugnacious diathesis, and the impossibility of deciding, when doctors disagree; or to the want of co-operation among scientific and practical men, or to what other cause we are to attribute this fatality, we shall not now stop to inquire; perhaps those who have access to the minute-book of the Committee of the College, are the only persons who can solve the problem.

Like ancient Gaul, the Pharmacopaia is divided into three parts: one assigned to some preliminary matters respecting weights and measures; the second to the Materia Medica; and the last to the preparations and compounds. We shall follow Mr. Phillips' example in passing over the two former divisions without remark. The third is subdivided into sections, of which the first treats of " Acids,” alphabetically arranged.

The term "diluted acetic acid" is properly enough applied to distilled vinegar, but the process of distillation might well have been rejected; for all medical purposes a dilute acid, composed of 1 part of the concentrated acetic acid, contained in the Materia Medica, and four parts of water, is preferable. Of this mixture, or of distilled vinegar, the sp. gr. should be about 1009, and 1000 parts should saturate 145 of crystallized carbonate of soda: 50 grains of real acetic acid saturate, according to our translator, 153 grains of this salt, and upon this datum the following is the composition of the dilute acid of different specific gravities:

Of these acids, the two first are the average strength of distilled vinegar, and the two last that of the concentrated acetic acid, as now generally prepared by the vinegar-makers from pyroligneous acid.

Benzoic Acid is an article which might very well be struck out of the Pharmacopoeia; the process, however, now directed is preferable to that of the last edition.

A process for obtaining Citric Acid is given in this division, but it also has a place among the articles of the Materia Medica, and is so rarely prepared except by the manufacturer upon an extended scale, that the directions here given might well have been dispensed with. Mr. Phillips tells us that an ounce of water at 60° dissolves 10 drachms of crystallized citric acid; and such solution saturates about 20 drachms of crystallized carbonate of soda. Nine drachms and a half of citric acid dissolved in a pint of distilled water, give, he says, a solution equal in strength to lemon juice.

We shall quote the article " Muriatic acid" entire, that our readers may judge of the method which the translator pursues in his remarks and of their general usefulness to students and practitioners.

Muriatic Acid.

"Take of dried muriate of soda, two pounds, Sulphuric acid by weight, twenty ounces, Distilled water, a pint and a half;

"First mix the acid with half a pint of the water in a glass retort, and to these, when cold, add the muriate of soda; pour the remainder of the water into a receiver; then, adapting the retort to it, let the muriatic acid distil into the water from a sand-bath, the heat being gradually raised until the retort becomes red hot.

"The specific gravity of muriatic acid is to that of distilled water as 1.160 to 1.000.

"One hundred and twenty-four grains of crystallized subcarbonate of soda, are saturated by 100 grains of this acid.

"Process.-The nature of common salt, and the production of muriatic acid, are explained by two theories, both of which I shall state, because, from the name of muriate of soda which the college retain for common salt, it would appear that, as a body, they have not adopted the generally-received doctrines of Sir H. Davy on these subjects.

"On the supposition that muriatic acid is an undecomposed body, the explanation of its production is the following: Common salt, or muriate of soda, is a compound of muriatic acid and soda, and when it is mixed with the sulphuric acid, this, owing to its greater affinity for soda, expels the muriatic acid from it, which, being gaseous, and having considerable affinity for water, rises in the state of vapour with it, and is condensed in the receiver into liquid muriatic acid. The sulphuric acid and soda remain in the retort in the state of sulphate of soda.

"This process will be explained by the annexed diagram: