NEWS the compassionate sympathy of true believers. While I consider the work far from being as complete as it should be, and for that as well as other reasons its publication in detail may be delayed for some time, yet I think what can now be said of sufficient importance to be brought before this meeting. I propose, in this discussion, to maintain the mainly practical standpoint assumed by Prof. Johnson himself. I shall therefore leave out of consideration the performance of such exhaustive investigations of all the physical and chemical properties of the soil, as have been made in some cases, for special purposes, e.g., by Prof. Mallet, on some of the cotton soils of Alabama. If the investigation of each soil, to possess practical importance, requires from three to six months labour, we may as well, for practical purposes, consider such researches out of the question for the present. We want something analogous to the metallurgical assay of minerals, as distinguished from their complete ultimate analysis. So far, therefore, as the agricultural qualities of a soil may be inferred and approximately estimated by an experienced eye, I would relieve the chemist from the exact numerical determination, .g., of the power of absorbing heat from the sun, the specific heat, the "water-holding" power, the capillary coefficients, &c. However necessary for theoretical investigations, I hold that, for practical purposes, these laborious determinations may in most cases be dispensed with; since from what has already been done, or what can be done with a few typical soils, we may infer the comparative magnitude of these coefficients with a sufficient degree of approximation. The amount of labour bestowed on each soil by Dr. Peter, as reported in the Kentucky and Arkansas surveys, approaches very closely the limit beyond which the immediate advantages to be derived from such knowledge of soils as analysis may impart, would seem, to many, disproportioned to the expenditure involved. How very modest we are, truly, when a purely scientific object is involved, whose immediate practical apptication is not obvious at a glance! In what other branch of technical science would it be thought admissible to proceed without obtaining such knowledge of the prime materials as chemistry may afford, even if no immediate application of this knowledge be foreseen? Our public treasuries are constantly drawn upon for hundreds of thousands of dollars, in behalf of objects of at least questionable usefulness. Yet Prof. Johnson-seems to have thoroughly satisfied our state geologists that they are not justfied in giving the virgin soils of their respective States the benefit of such light as chemistry may even now confessedly afford; apart from the important general inferences which may fairly be expected to be drawn hereafter from the history of their cultivation. How are we to advance in our knowledge of soils if we abandon as hopeless the determination of their chemical character? Are the proofs that have been brought against the utility of soil analyses really of such a character as to justify so grave an omission? an omission, too, which in many cases cannot hereafter be supplied. Even in the comparatively youthful State of Mississippi, I have found difficulty in obtaining reliable specimens of some soils, whose great productiveness had led to their cultivation by the earliest settlers, over the entire area of their occurrence. I question the propriety of this omission, and the justice of the testimonium paupertatis thus inflicted upon agricultural and analytical chemistry. To define my position, I premise that 1. I fully agree with Prof. Johnson as to the comparative uselessness of a single analysis giving the percentages of soil ingredients found, in ordinary cases. It is only when such analysis demonstrates the great abundance, or very great deficiency, of one or several primarily important ingredients, that, by itself, it conveys information of considerable practical importance. Note that such cases are not altogether infrequent, even in virgin soils. 2. I agree that an "average soil" is a non ens, except as referred, comparatively, to a particular set of soils closely related in their origin. 3. Also, that the claim of being able to detect the minute differences caused by cropping without return to the soil, is precarious, and perhaps beyond the power of our present analytical resources. 4. I further admit that, ordinarily, the analysis of soils long cultivated, and treated with manures, can give but little and very partial information as to the condition and composition of the soil; from the great difficulty, if not impossibility, of obtaining fair representative specimens. 5. Furthermore, that to designate soils by the names of the Cretaceous, Carboniferous, or Silurian strata they may happen to overlie, is very loose practice; since in most cases they are derived from Quaternary deposits, which may or may not have been influenced in their composition by the subjacent rocks. On the contrary, I demur, in the first place, to the broad assertion that "it is practically impossible to obtain average specimens of the soil," as inapplicable to a very large class, especially of virgin soils, covering large areas with a uniformity of character corresponding to that of subjacent formations, from which they have been directly derived, by substantially identical and uniform, or uniformly variable processes. The importance of this exception is not, it is true, very obvious in the stony fields of New England (such as discouraged Prof. Johnson in his vacation trip to Northern New York), or in fact, in any district where a great variety of formations has directly contributed toward forming the soil, and "chunks" of undecomposed minerals are diffused through it. In such cases, the analysis of the rock which has predominantly contributed to the mass of the soil proper, would be a more correct index of the prevalent characteristics of the latter than if itself were taken in hand. And from such analyses we could at least deduce what ingredients, and in what form, it would certainly be useless to add to the soil. But when we come to the great plains of the West and South-West, whose soils are consistently derived from wide-spread quaternary deposits, composed of materials almost impalpable, save as regards siliceous sand, or even the rolling uplands of the Gulf States, whose subsoil stratum of "yellow loam" can only be diluted, but not otherwise changed, by the admixture of the underlying drift, leached long ago of everything soluble in carbonated water or available to plants: the objection based upon the supposed impossibility of securing representative specimens, becomes obviously untenable, as I shall hereafter show from the close correspondence in the composition of soils, and especially sub-soils, from widely distant portions of the State, derived from the same geological (quaternary) stratum. A word in regard to the "freaks and accidents " mentioned by Prof. Johnson as liable to make sport of the devoted analyst. Undoubtedly such errors must be ultimately provided against by multiplication of analyses (not necessarily of the same acre, but of other corresponding specimens, in the sense mentioned above); and while questioning the efficiency of a bird or squirrel in vitiating a properly taken sample of soil, I must admit the disastrous consequences which might result if a dog, cow, or horse were similarly concerned. No specimen of “virgin soil" can, of course, be obtained where such animals usually do congregate. But, as a rule, it is not all difficult to avoid such places; while the chance of accidentally hitting upon a sporadic animal deposit in the broad woods or prairies is singularly small, and is notably diminished by the circumstance, that an attentive observer (and none other should take soil specimens) will be able to distinguish such localities for years, by the peculiarity of their vegetation. I will remark, however, that I consider the sampling of a soil with a view to securing a representive specimen, as a matter second in difficulty and delicacy only to the analysis itself; that I rarely have thought it worth while to analyse specimens sent by other than intelligent persons specially instructed by me; and even then have frequently had to reject them, from their having obviously been taken at an improper locality, e.g., near a footpath, by the side of a fence, on a partially denuded hillside or ravine, in the bed of a run, at the foot of a tree, &c. The question of depth must, in my view, be left to be determined by the circumstances of each case, except in so far as the extreme depth to which tillage may cause the roots of crops to reach, must be within the limits of the samples taken. Of these, one should ordinarily represent what, under the usual practice of tillage, becomes the arable soil; another the subsoil not usually broken into; a third will in most cases be useful to show what materials would be reached were the land to be underdrained. As a rule, I have taken no specimens of soil to a less depth than six inches, and as much deeper as uniformity of colour reached-for obvious reasons. But in special cases, when important differences were suggested by the aspect of the soil and subsoil, they have been separately examined, at whatever depth the change of colour might occur. With soils of the character referred to, samples selected and taken with due care, and strict attention to thorough intermixture, both in the field and subsequently in the laboratory, I am unable to see why even two grammes may not correctly represent the characteristics of a 1000 acre tract. Not that every point of that tract would be likely to give the same percentage result, perhaps, especially as regards the surface soil, which might in places be more clayey or more sandy than the sample analysed. Still, the relative proportions of the soil ingredients, and their degree of availability, would remain substantially the same; the wider range and readier penetration of roots in sandier soils, making up, within certain limits, for the smaller percentage of available ingredients in a given bulk, as compared with more clayey ones. From the fact that the atmospheric surface water must, in its course, inevitably have a tendency to bring about such inequalities, by carrying forward the finer particles of the soil in larger proportion than the coarser ones, as well as from the greater influence of vegetation, we shall, in the series of analyses, made a postulate by Prof. Johnson, expect to find a closer agreement between those of subsoils than those of surface soils. Such I find to be very decidedly the case; so much so that I habitually look to the former as the most reliable index of a soil's distinctive character. To this there can be no legitimate objection, when, as in all the upland soils now under consideration, the surface soil is directly derived from the subsoil, and its depth is less than thorough culture would give to the arable soil. As regards the analysis itself, I premise that I have always found even the most chemically pure" reagents sold by dealers quite inapplicable to the purpose of soil analysis. From first to last, I have prepared or purified these myself; and, as regards the acids, especially hydrochloric, I have found it necessary to reject, as a rule, even the purest, after keeping it for a few weeks in a glass bottle. The same is true, and perhaps in an aggravated degree, of aqua ammoniæ. The severe ordeal of slow evaporation on a bright platinum foil will rarely be passed by ammonia a fortnight old; and still less frequently by hydrosulphide of ammonium. consideration, however, I found that the (sensibly constant) error so introduced would not, when allowed for, amount to more than the differences between two analyses of one and the same material, or vitiate in any serious degree the conclusions arrived at. Nevertheless, I shal! hereafter, to the utmost possible extent, carry on all operations liable to introduce errors on this score, in platinum and porcelain vessels. as advised by Bunsen. As regards Dr. Peter's failure to determine the amounts of soluble silex, nitric acid, ammonia, chlorine, and the degree of oxidation of the iron, I agree that the former is desirable, not only because, whether "essential" or not, some plants do habitually absorb it in very large quantities, and it might be best to let them have it; but also because it is a desirable index of the degree of decomposition which the soil silicates have undergone. I have therefore made this determination regularly, by boiling with solution of sodium carbonate. In a series of these determinations, an unmistakable relation between the soluble silex and the amount of lime in the soil becomes manifest; as might, indeed, have been foreseen. As regards nitric acid, the consideration suggested by Prof. Johnson himself, viz., that its quantity must be exceedingly variable, within short periods, in one and the same soil, seems to me a sufficient dispensation from the laborious determination. The same holds good, in a measure, for ainmonia. Its quantity varies continually in the soil, as it does in the atmosphere; its chief absorbers in the soil are "humus" and clay. Where these prevail largely, ammonia can scarcely be deficient as a nutritive ingredient to an injurious extent; albeit, more might doubtless be beneficially added. Moreover, the characteristic effects of ammonia on vegetation are sufficiently obvious (in "running to weed") to render its determination in virgin soils, laborious and even uncertain as it is, a matter of compara tively little practical consequence, however great might be its theoretical interest. As for the determination of the degree of oxidation of iron, I confess I fail to see its practical bearing. When ferric oxide is present, plants surely can have no difficulty in reducing the modicum they need to a soluble condi tion. When ferrous oxide exists to any great extent, it indicates a want of drainage, and manifests itself both in the colour of the soil and in the poisonous effect on vegetation. But farmers surely do not need the aid of chemical analysis to tell them that their soil needs drainage and aëration! A determination made to-day would be of no value to-morrow, if the soil had been ploughed in the interval. Finally, Dr. Peter docs determine chlorine in the treatment of soils with carbonated water, though it is not put down in the general analysis. However, the soluble chlorides, like the nitrates, are so constantly liable to variation, and, as experience shows, so little likely to be deficient in the soil, that its omission would not be a serious practical objection. (To be continued.) PROCEEDINGS OF SOCIETIES. MANCHESTER LITERARY AND PHILOSOPHICAL SOCIETY. Ordinary Meeting, December 10th, 1872. Chair. Armed with these, and a multitude of other precautions, usual and unusual, to secure the utmost possible accuracy; always treating the soil with the same large excess of acid of uniform strength, and precipitating all corre sponding precipitates as much as possible from the same volume of liquid; using none but the best Bohemian J. P. JOULE, D.C.L., LL.D., F.R.S., &c., President, in the glass, and platinum vessels, and filters specially extracted -operating, in short, as uniformly as the nature of the materials would permit: I confess I felt considerable confidence in the correctness of my results, until the experiments made in Bunsen's laboratory, on the solubility of glass vessels, gave rise to unpleasant doubts. On "Observations of the Meteoric Shower of November 27th, 1872." I. By E. W. BINNEY, F.R.S., F.G.S.-On the 27th November last, at Douglas, in the Isle of Man, my attention was called by an inmate of my house to numerous meteors in the sky. On going out of doors about 7.45 p.m., they were seen radiating from a point in Andromeda and falling in all directions towards the horizon, some not proceeding far down before they disappeared, whilst others travelled to a much greater distance. The sky was perfectly clear for three hours, during which time I observed them, and they appeared in all directions to be equally numerous except during the last hour. Some were as large as a star of the first magnitude and others were only just perceptible. Nearly all of them appeared to leave tails in their course, which were generally straight, but some of them were curled. In colour most of them were white or yellowish white, but some of the larger ones were of a reddish tinge. At about 7.45 p.m. six were noticed at one time. At 8.45, on looking at about a quarter of the space of the heavens, towards the west, I counted during a minute 21, 11, 24, and 12 respectively. This would give an average of 17 per minute; assuming that the other three portions of the heavens afforded as many, and to me the meteors appeared to be about equally dispersed, so there would be probably about 68 per minute during the two first hours I observed them. At eleven o'clock they were still falling, but not so numerously. The early part of the evening was rainy, but it cleared up shortly before seven, and I am informed that meteors were then observed. On the 3rd December inst., at 8.45 p.m., there was visible an aurora in the form of a beautiful arch of a yellowish white colour, extending from east to west, and reaching up to the lower parts of Ursa Major. A slight trace of streamers was seen on the top of the arch. 2. By JOSEPH BAXENDELL, F.R.A.S.-The early part of the evening of the 27th of November was cloudy, and the meteors were not seen till about 10 minutes to 7, when a partial clearing occurred. It soon became evident that they belonged to a distinct meteoric stream, and my attention was therefore chiefly directed to the determination of the position of the radiant point. The observations were, however, frequently interrupted by clouds, and at no time was the sky entirely cloudless. The intervals of observation and the number of meteors whose tracks were observed with sufficient precision to be of use in the determination of the position of the point of divergence were as follows: II 54 12 19 G. M. Time.. Number of Meteors. 65 54 80 9 31 7 15 ΙΟ II 33 12 7 The total number was 271, and of these 266 had the points of intersection of their paths in an elliptical area of 12 degrees long and 8 or 9 degrees broad, the centre of which was in right ascension 22 degrees, and north declination 44 degrees, near the small star Chi Andromedæ. Three of the remaining five had their radiant point in the constellation Cassiopeia. The average brightness of the meteors was equal to that of a star between the 3rd and 4th magnitudes; many, however, were equal to stars of the 1st magnitude, and several of the finest exceeded the planets Jupiter and Venus when in their positions of maximum brilliancy. The colour for the most part was white; in many, however, it was yellow or orange, and in several of the brightest it was at first white and then a deep red immediately before extinction. Most of the brighter meteors left luminous trains, but these seldom remained visible for more than a few seconds. The apparent velocity of movement was decidedly less than that of the 13th of November meteors. The paths of many of the meteors were more or less curved, and many of them formed curves of double curvature. It was observed that the radiant point appeared to move to the eastward during the progress of the shower, so that the mean position, from the observations made up to 8h. 34m., was about 3 degrees to the west of the position derived from the observations made afterwards. The mean position of the radiant point, as given above, shows that the course of the stream coincides almost exactly with the orbit of Biela's comet. 3. By ALFRED BROTHERS, F.R.A.S.-The sky at Cheetham Hill, and I may therefore have had a better Wilmslow appears to have been less clouded than at 5.50 to 8.30 there was very little cloud, and during that view of the display than Mr. Baxendell. From about the meteors were falling very nearly at the same rate. There was no difficulty in determining the radiant pointy Andromedæ being about the centre. favourably for determining their radiancy than this one. Probably few meteor showers have ever been seen more The result of careful counting by myself and Mr. Wilde naked eye. The N.W. horizon was distinctly illuminated was that from 1800 to 2c00 per hour were visible to the about 8 o'clock by auroral light, and the whole sky was more or less luminous during the whole time. Mr. W. BOYD DAWKINS, F.R.S., brought before the notice of the Society some remarkable forms of stalagmites which he had obtained from some caves near Tenby. In one cave the calcareous deposit had taken the form of small mushrooms standing close together with a stem not much thicker than a hair, that covered every part of the surface, and in some places had their tops of a dull red colour, and in others of a snow white. In a second every pool was lined with most beautiful crystals of a dog-tooth spar, while from the roof there descended slender stalactitic pillars, some snow white and others of a deep red, and most of the thickness of a straw. They stood almost as closely together as the stems of wheat in a wheat-field. In a few pools where the drip caused constant agitation of the water, pea-like rounded concretions of carbonate of lime were formed, some of which, polished by friction, were almost as lustrous as pearls, and might fairly be termed "cave-pearls." "On the date of the Conquest of South Lancashire by the English," by W. BOYD DAWKINS, M.A., F.R.S. "On some Human Bones found at Buttington, Montgomeryshire," by W. BOYD DAWKINS, F.R.S. "On the Electrical Properties of Clouds and the Phenomena of Thunder Storms," by Professor OSBORNE REYNOLDS, M.A. The object of this paper is to point out the three following propositions respecting the behavour of clouds under conditions of electrical induction, and to suggest an explanation of thunder storms based on these propositions and on the assumption that the sun is in the condition of a body charged with negative electricity: an assumption which have already made in order to explain the Solar Corona, Comets' Tails, and Terrestrial Magnetism. 1. A cloud floating in dry air forms an insulated electrical conductor. 2. When such a cloud is first formed it will not be charged with electricity, but will be ready to receive a charge from any excited body to which it is near enough. 3. When a cloud charged with electricity is diminished by evaporation, the tension of its charge will increase until it finds relief. I do not imagine that the truth of these propositions will be questioned, but rather that they will be treated as self evident. However, as a matter of interest, I have made some experiments to prove their truth, in which I have been more or less successful. Experiment I was to show that a cloud in dry air acts the part of an insulated conductor. The steam from a vessel of hot water was allowed to rise past a conductor, the apparatus being in front of a large fire, so that the air was very dry. When the conductor was charged the column of vapour was deflected from the vertical to the conductor both for a positive and negative charge. Experiment 2 was made with the same object as Experiment I. A gold leaf electrometer was charged so that the leaves stood open and then a cloud made to pass by the insulated leaves. As the cloud passed they were both attracted. This experiment was attended with considerable difficulty, as the moisture from the steam seemed to get on to the glass shade over the gold leaves and so form a charged conductor between the leaves and cloud. The cloud was first formed by a jet of steam from a a pipe, then by the vapour from a vessel of boiling water, and lastly, by a smoke ring or rather a steam ring. By this latter method an insulated cloud was formed, which, as it passed, was attracted by the charged leaf. Of the two latter propositions I have not been able to obtain any experimental proof. I made an attempt, but failed, through the bursting of the vessel in which the cloud was to be formed. I hope, however, shortly to be able to renew the attempt, and in the meantime I will take it for granted that these propositions are true. Faraday maintained that evaporation was not attended by electrical separation unless the vapour was driven against some solid, when the friction of the particles of water gave rise to electricity. So that unless there were some free electricity in the steam or vapour before it was condensed none could be produced by the condensation, and hence the cloud when formed would be uncharged. In the same way with regard to evaporation, unless, as is very improbable, the steam into which the water is turned retains the electricity which was previously in the condensed vapour; the electricity from that part of the cloud which evaporates must be left to increase the tension of the remainder. So that, as a charged cloud is diminished by evaporation, the tension of the charge will increase, although the charge remains the same. I will now point out what I think to be the bearing which these propositions have on the explanation of thunder storms. In doing this, I am met with a great difficulty, namely, ignorance of what actually goes on in a thunder storm. We seem to have no knowledge of any laws relating to these every-day phenomena; in fact we are where Franklin left us-we know that lightning is electricity and that is all. It is not, I think, decided whether the storm is incidental on the electrical disturbance or vice versa, i.e.. whether the electricity causes the clouds and storm or is a mere attendant on them. Nor can I ascertain that there is any certain information as to whether, when the discharge is between the earth and the clouds, the clouds are positive and the earth negative, or vice versa. Such information as I can get appears to point out the following law that in the case of a fresh-formed storm, the cloud is negative and the earth positive; whereas, in other cases, the cloud is positive and the earth negative. Again, thunder storms move without wind or independently of wind; but I am not aware whether any law connecting this motion with the time of day, &c., has ever been observed, though it seems natural that, however complicated by wind and other circumstance, some such law must exist. In this state of ignorance of what the phenomena of thunder really are, it is no good attempting to explain them. What I shall do, therefore, is to show how the inductive action of the Sun would necessarily cause certain clouds to be thunder clouds in a manner closely resembling, and for all we know identical with, actual thunder storms. In doing this I assume that the thunder is only an attendant on the storm and not the cause of it; and that many of the phenomena, such as forked and sheet lightning, are the result of different states of dampness of the NEWS air and different densities in the clouds, and really indicate nothing as to the cause of electricity. In the same way, the periodicity of the storms is referred to the periodical recurrence of certain states of dryness in the atmosphere. Thus the fact that there is no thunder in winter is assumed to be owing to the dampness of the air, which allows the electricity to pass from and to the clouds quietly. What I wish to do is to explain the cause of a cloud being at certain times in a different state of electric excitation to the earth and other clouds, and of this difference being sometimes on the positive side and sometimes on the negative, that is to say, why a cloud should sometimes appear to us on the earth to be positively charged, sometimes negatively, and at others not to be charged at all. The assumed condition of the sun and earth may be represented by two conductors S and E, acting on one another by induction, the sun being negative and the earth positive. The distance between these bodies is so great that the inductive action would not be confined to those parts which are opposed, but would in a greater or less degree extend all over their surfaces, though it would still be greater on that side of E which is opposite to S than on the other side. The conductor E must be surrounded by an imperfectly insulating medium to represent damp air. The formation of a cloud may then be represented by the introduction of a conductor C near to the surface of E. Such a conductor at first having no charge would attract the positive electricity in E and appear by reference to E to be negatively charged. If it was near enough to E, a spark would at once pass, which would represent a flash of forked lightning. If it were not near enough for this it would obtain a charge through the imperfect insulation of the medium. Such a charge might pass quietly or by the electric brush. When the cloud had obtained a a charge it would not exert any influence on the earth, unless it altered its position. But if the heat of the sun caused part of the cloud to evaporate the remainder would be surcharged and appear positive. Or if C approached E then C would be overcharged, and a part of its electricity would return, and on its return it might cause positive lightning. Thus, suppose that after a cloud had obtained its charge part of it came down suddenly in the form of rain. As the rain came lower its electric tension would increase until it got near enough the ground to relieve itself with a flash of lightning, almost immediately after which the first rain would reach the ground. It has often been noticed that something like this often takes place; it often begins to pour immediately after a flash of lightning, so much so that it seems that the electricity had been holding the rain up, and it was only after the discharge that it could fall. This, however, cannot be the case, for the rain often follows so quickly after the flash that there would not have been time for it to fall from the cloud unless it had started before the discharge took place. If, on the other hand, C receded from E, it would again be in a position to accept more electricity, or would again become negative. In this way, a cloud in forming, or when first formed, would appear negatively charged; soon after it would become neutral, and then if it moved to or from the earth it would appear positively or negatively charged. If the air was very dry, as it is in the summer, any exchange of electricity between the earth and the cloud would cause forked lightning, in the winter it would take place quietly, by the conduction of the moist atmosphere. In this way then there would sometimes be positive, sometimes negative lightning; sometimes the discharge would be a forked flash or spark, sometimes a brush or sheet lightning. And if clouds are formed in several layers, as would be represented by another conductor, D, outside C, then, in addition to the phenomena already mentioned, similar phenomena would take place between C and D; and if, in addition to this, we were to assume that there are other clouds in the neighbourhood, the he is acquiring the facts here given he will be laying the phenomena might be complicated to any extent. foundation of a truly scientific education. And if, further, the motion of the sun is taken into account; as the conductor S moves round E the charges in D and E would vary, accordingly as they were more or less between S and E and directly under the induction of S; i.e., the charge in a cloud would appear to change owing to the motion of the sun; thus, a cloud that appeared neutral at mid-day would, if it did not receive or give off any electricity, become charged positively in the evening. With regard to the independent motion of the clouds, there are several causes which would effect it. For instance, a cloud whether it appeared on the earth to be negatively or positively charged, would always tend to follow the sun, though it is possible this tendency might be very slight. Again, one cloud would attract or repel another, according as they were charged with the opposite or the same electricities; and in the same way a cloud would be attracted or repelled by a hill, according to the nature of their respectfve charges. Such, then, would be some of the more apparent phenomena under the assumed conditions. So far as I can see, they agree well with the general appearance of what actually takes place, but, as I have previously said, the laws relating to thunder storms are not sufficiently known to warrant me in doing more than suggesting this as a probable explanation. In these remarks I have said nothing whatever about what is called atmospheric electricity, or the apparent increase of positive tension as we proceed away from the surface of the earth. I do not think that this has much to do with thunder storms. If the law is established, it seems to me that it will require some explanation, besides merely that of the solar induction acting through the earth's atmosphere on to the surface of the earth. would rather imply that the sun acts on some electricity in the higher regions of the earth's atmosphere, and that electricity in these regions acts again on the surface of the earth; but, however this may be, the effect of the assumptions described in this paper would be much the same. NOTICES OF BOOKS. It Introduction to Inorganic Chemistry. By WILLIAM GEORGE VALENTIN, F.C.S., Principal Demonstrator of Practical Chemistry in the Royal School of Mines and Science Training Schools, South Kensington. THE student of chemistry must be sometimes at a loss to distinguish for himself the best text-book. Each of the numerous volumes from which he may select has its peculiar feature: and the existence of this plurity of teaching-methods is suggestive of the fecundity of the science, But many text-books unhappily differ in little more than the authors' names; in them there is given description of the orthodox method of preparing hydrogen from water, sulphuric acid, and zinc, as well as orthodox methods of obtaining other elements; some books vary the process by recommending expensive apparatus, others go to the opposite extreme of imagining all students trained mechanicians or artizans. Few of the text-books detail fully the method of preparing, say hydrogen, from the action of sodium upon water, the decomposition of water by electrolysis, by heated oxidisable bodies, &c. ; but among the number who are content to treat chemistry as an experimental science, Mr. Valentin ranks in the first order. His book records the neatest modes of preparing an experiment, and the bearing of the experiment upon the general theory of chemical science. As a practical handbook the student need go in search no farther, for while CORRESPONdence. CHEMISTRY OF ACID MANUFACTURE. To the Editor of the Chemical News. SIR,-In your report of the transactions of the Manchester Literary and Philosophical Society, page 307 of your last issue, you give an abstract of a paper "On some points in the Chemistry of Acid Manufacture," by H. A. Smith, F.C.S. Is it in your power to give the whole of the paper? for as the report at present stands, I venture to think it is of but little service, no experimental data being given-no descriptions of the modes of experimenting. Indeed, it is temptingly provocative of adverse criticism, which further explanation might remove, and so convert the paper into a really valuable contribution on a most interesting subject.-I am, &c., CHARLES F. BURNARD. Dec. 28, 1872. ANALYSIS OF MANURES. To the Editor of the Chemical News. SIR,-Having just seen Mr. Reynolds's proposition for a more correct scale of valuation for the constituents in artificial manures, I would like to draw his attention, as a primary question, to the means of ascertaining the relaAs yet it seems beyond the means of ordinary analyses. tive proportions of the ingredients he names in manures. Mr. Reynolds admits a difference in the value of mineral and bone phosphates. If, then, a farmer buys a quantity of manure under the common name of " Dissolved bones" if he sends a sample of this to a chemist, and requests to know whether all the phosphates present are bone, and if not, how much of them are from minerals, can the chemist tell this? We suspect not. We have heard chemists of very high standing confess that when dissolved they cannot tell, and even the portion not in a soluble condition, if equal ground, the proportions of the one and the other cannot be given. This is what farmers wish to know, and then the true value is of easy determination; and so long as bones are nearly double the price of mineral, and no positive means of determining when and to what extent they are mixed, the farmer will be at the mercy of the adulterator. The relative quantity of ammonia as such in a manure and ammonia latent is within ordinary analysis, and ought to be determined and relatively valued-a matter long overlooked. I would suggest that Mr. Reynolds turn his attention to the determining the relative quantities of bone and mineral phosphates when they are mixed in a manure.—I am, &c., |