From the lumber-master's books, for the year 1845, we learn that there was received and measured

It may be proper to remark, that the vessels engaged in transporting wood, lumber, &c., to St. Louis, are not embraced in the reports of the harbor-master.

We have already extended this article to a much greater length than we designed, and must therefore conclude with a few remarks from the Missouri Republican :—

"It may be properly assumed, that trade, shipping, or business, cannot be diverted, to any considerable extent, by mere artificial means, from channels which nature, the country, population and their necessities, have given it. If St. Louis, then, commands at this early day, (early at least in her commercial history,) a large commerce, and this, too, without artificial aid or national encouragement, it is but a rational conclusion, that it cannot be diverted, nor can any amount of capital supply the place of the rivers which constitute her great highways.

"It is useless to discuss this point. The position and natural advantages which New York enjoys, give her a commercial pre-eminence: the want, or absence of these advantages, have caused other cities on the seaboard, once her superiors in wealth, population and trade, to become her tributaries. A nation, justly appreciating the advantages given to particular localities, by nature, whilst it should not neglect any, should certainly feel bound to protect and foster those in which the greatest number are interested. Without vanity, we think we may claim for St. Louis, that she is one of those great points designed to constitute a commercial depot for the whole country. Her position is as essential to the east, as it is favorable to the people who live in its vicinity. Her commerce furnishes supplies for foreign trade, and a home consumption of the products of that trade. Why, then, is her harbor, its improvement and protection, placed beyond the pale of constitutional assistance from the general government?

"If the harbor of New York were in imminent danger of being destroyed-if vessels could not enter or depart without grounding, and being subject to much peril, delay and expense-would any one say it was not the business of the general government immediately to remove the difficulty, and, as far as practicable, prevent its recurrence? The constitutional power, and the duty of the United States government, to protect and improve harbors looking out upon the sea, we believe, has never been questioned or doubted by the most ultra abstractionist. Yet New York, and many of the harbors on the coast and upon the lakes, are better situated for their own protection, than the city of St. Louis. If an obstruction should occur in the harbor of New York, the jurisdiction of the city, or state, would probably reach far enough to remove it-at least, we suppose it would reach to the Jersey shore on one side, to the sea indefinitely, and quite across East river. The same might be said of Boston, Baltimore, and other ports. But St. Louis is differently situated; the jurisdiction of the city, or state, extends only to the middle of the main channel of the Mississippi river. With the jurisdiction of Illinois over the other half of the river, no power but that of the United States government can interfere. The Mississippi is a national highway, beyond the jurisdiction of states or cities. New York, Boston, or Buffalo harbors, are no more nor less free to the nations of the world than this river. Yet, will it be contended, that the people of New York, Boston and Buffalo, should protect or improve these national harbors, at their own expense, when all nations may enjoy their benefits? Upon the seabo ard and the lakes, the people directly interested in the preservation of the harbors, have jurisdiction, which gives a power which this city has not over the Mis

sissippi river. They can, of themselves, improve their harbors; we cannot, because of a want of jurisdiction on both shores of the river. Can it be, that the Constitution of the United States is so framed, that Congress may, with the authority of that instrument, assist those having full power to help themselves, and yet that it cannot constitutionally help those who are stripped of all authority to do so? The proposition appears to be too absurd for argument."

Art. VI.-CHEMISTRY APPLIED TO COMMERCE AND MANUFACTURES:

A NEW, SIMPLE, AND ACCURATE METHOD OF ASCERTAINING THE COMMERCIAL VALUE OF POTASH AND SODA.

THE various methods for ascertaining the amount of potash and soda contained in commercial pearlash and soda, or rather the carbonate salts of these bases, have been collectively termed alkalimetry. Their importance in commerce, to manufactures and consumers, has induced many chemists to direct their attention to this subject. All have, however, followed the same principle, first laid down by Descroizelles, of which the methods of Gay-Lussac, and other chemists, are only modifications, having for their object to render the execution of the operation more easy, and the results more certain.

The conditions requisite for the success of these methods may easily be satisfied by careful manipulation, correct apparatus, practice and patience, when the potash or soda to be tested are not mixed up with salts or impurities which neutralize the sulphuric acid in the same manner as the carbonate alkalies. But salts of this kind are always contained, to a greater or less amount, in all ashes of plants, and especially in artificial soda. In the former, these consist of alkaline silicates and phosphates, along with carbonates, silicates and phosphates of the alkaline earths; in the latter, of sulphite and hyposulphite of soda, sulphuret of sodium, and in the crude soda, moreover, of carbonate of lime and sulphuret of calcium. The insoluble salts of the earths may be easily removed by treating the sample with water and filtering, but the separation of the soluble salts is either very difficult, (those sodas which contain sulphites or alkaline sulphurets must, before they can be tested, be fused with chlorate of potash,) or quite impossible; such is the case when the impurities consist of hyposulphites, silicates and phosphates. The presence of these salts, when they occur in any quantity, renders the examinations of potashes and sodas by the methods hitherto in use far from accurate: the per centage amount of carbonate alkalies in the pearlashes and sodas is always indicated too high, to the disadvantage of the buyer. The importance of this objection will be most clearly evident from the fact, that most of the commercial sodas contain such amount of sulphite and hyposulphite of soda, that only approximative results can be obtained with the methods hitherto in use, (sometimes 3, 4, 6, and more per cent too much,) a circumstance which increases its importance, as the artificial soda has now nearly driven that obtained from plants entirely out of the market.

The mode of testing which we have adopted, and which we will now describe, is founded on a principle not less simple than the old method, but is exactly the reverse of it. To find the amount of a compound body, the constituents of which are in a known, definite and invariable proportion, it is not requisite to determine the amount of all the constituents; a know

ledge of the quantity of the one or of the other allows of finding out the amount of the whole. The object of the examination of potashes and sodas is the determination of the carbonated alkalies contained in them. According to the old method, the amount of alkali was determined by measuring off the acid required for neutralization; in our method, it is the carbonic acid which is in combination with the alkalies, which is determined. For this purpose, we have constructed a new apparatus, in which the drying of the carbonic acid is not effected, as in former ones, by means of chloride of calcium, but in the most simple manner by the same sulphuric acid which expels the carbonic acid from its combinations. It admits of a considerable quantity of substance being decomposed, and there need be no fear of having employed too little acid. The water is absorbed more completely than with chloride of calcium, and it is not requisite to employ heat, as the sulphuric acid itself performs this office. The accuracy and constancy of results, even with an ordinary balance, and the ease with which the results may be obtained by every one, have far exceeded our expectations; and lastly, the apparatus is so simple, that it may readily be constructed by any person, as will be evident from the annexed wood-cut.

A

B

A and B are two wide-mouthed bottles, of which A contains from 4 to 5 ounces of water; B is of somewhat smaller capacity, (from 3 to 4 ounces.) These vessels are closed with corks, each of which is bored twice, and into which the glass tubes, b, c and d are fitted in the manner shown in the wood-cut. The extremities of all the tubes are open; when in use, the tube b is closed at its extremity with a piece of wax. A weighed quantity of the substance is conveyed into A, which is then filled one-third with water; B is filled one-half with ordinary sulphuric acid. The corks are now fitted into the apparatus, which is then weighed. Some air is sucked out by the tube d, in consequence of which the air in the entire apparatus becomes dilated, and the sulphuric acid in B ascends the tube c, and a portion flows over into A; but as soon as this comes into the solution of the carbonate salt, a violent evolution of carbonic acid gas ensues. This, from the arrangement of the apparatus, is forced to pass through the sulphuric acid in B before it can escape through the tube d, the only opening in the apparatus, and in its passage, all moisture is per fectly absorbed and retained. When the sulphuric acid reaches the liquid in A, this becomes hot and expands, and also the air above it; on cooling, both reassume their original volume; and the result is, that a fresh portion of sulphuric acid flows into A as soon as the evolution of gas ceases; this is, moreover, assisted at the commencement of the operation, by some of the carbonic acid contained in A being absorbed by the still undecomposed carbonated alkali. However, to save time, it is far more simple, each time after evolution of gas has ceased, to draw more air through the tube d. In this manner, the operation may be finished in a few minutes. When the carbonate salt is entirely decomposed, which is immediately seen from no more evolution of gas resulting on the addition of fresh acid,

a somewhat large quantity of the sulphuric acid still contained in B is made to pass over into A by suction, which heats the liquid so much that the whole of the carbonic acid which had been absorbed escapes. When all evolution of gas has ceased, the wax is removed from the end of the tube b, and air drawn through at d, until the whole of the carbonic acid with which the apparatus was filled, is replaced by air. The apparatus is then allowed to cool, wiped dry, and weighed. The loss in weight indicates the amount of carbonic acid which was contained in the sample, with the greatest accuracy, and from this, the amount of carbonated alkalies contained in the pearlash or soda may be easily ascertained, as will be subsequently shown.

Before proceeding to describe the details in the practical execution of this method, we will take into consideration the influence which the foreign salts, such as chlorides, sulphurets, sulphites and hyposulphites, have when the above apparatus is employed for determining the value of commercial potash or soda. The presence of chlorides gives rise to no error, as from the diluted state of the solution of the sample not a trace of the liberated muriatic acid escapes. The injurious effects which would result from the presence of sulphurets, sulphites, and hyposulphites, are easily obviated by adding a small quantity of neutral chromate of potash to the solution of potash or soda under examination. Both the sulphurous acid and the sulphuretted hydrogen are decomposed on their liberation into water and sulphur, with formation of sulphate of the oxide of chromium, all of which remain in the solution.

The sources of error arising from the presence of foreign salts are therefore easily obviated; but there is still one other circumstance which must be taken into consideration. Can the commercial value of pearlash and soda be actually determined with accuracy from the ascertained amount of carbonic acid, or is the amount of carbonic acid in the soluble parts of the pearlash and soda in proportion to the quantity of alkali which is rendered caustic by treatment with lime, (which consequently determines their value,) in a definite and constant proportion, or is it indefinite and varying?

Were the latter view correct, then the new method would be false in principle; if, on the contrary, the proportion is constant and invariable, or, in case it is not, can be rendered so, then we can conceive of no objection that can be made to our mode of examination.

Pearlash and soda are universally considered to contain neutral carbonate of alkali; opinions contrary to this have been recently asserted by some chemists. According to one statement, the carbonic acid is said to be sometimes in smaller proportion to the alkali than in the neutral carbonate; according to others, it is sometimes higher. According to some, many potashes and sodas contain caustic alkali, together with the neutral carbonate; according to others, bicarbonate, sesquicarbonate, &c. We have examined into the truth of these statements, and have shown how the injurious influence of the anomalies may be obviated. But there is one source of error which our method has, in common with all the others; it is that carbonate of soda, supposing it to be present in pearlash, is calculated as carbonate of potash, and vice versâ. If, however, it is a question only of the definite equivalents of alkali, which are to be employed, as it were, merely as the bearer of a force to produce certain chemical effects, then a perfectly correct result is obtained; for by so much the smaller the equiva

lent number of soda is to that of potash, just that quantity of potash is brought into calculation, instead of soda. Or, in other words, we may say that the carbonic acid is proportional to the force and effect of the potash as well as of the soda, or of a mixture of the two.

With respect to caustic potash, this certainly occurs in the North American pearlashes, but we have never been able to detect it in the Illyrian, Bohemian and German kinds. Caustic soda occurs very frequently in the commercial sodas. The method of detecting these, and ascertaining their quantity, will be subsequently described.

Bicarbonate, or rather sesquicarbonate of potash or soda, is formed in pearlash and soda by the absorption of carbonic acid from the atmosphere, when they are exposed for a long time in contact with the air. We have found its quantity, in our experiments, to be generally very small, in most cases scarcely to be detected. To ascertain its presence, the solution of the pearlash or soda is treated with solution of chloride of calcium in excess, filtered, and ammonia added to the clear liquid, which will become immediately turbid, if it be present. It has, however, no influence on the result, for it is converted by a gentle heat into the neutral carbonate; and according to our method, the sample is always heated before being tested. Herrmann has recently denied the accuracy of the generally-received opinion, that the sesquicarbonate or bicarbonate of potash is converted by ignition into neutral salt. Numerous experiments and analyses which we have made, have proved the incorrectness of his results. Our experiments showed, in fact, that no combination containing more carbonic acid than the neutral salt could exist at a high temperature.

Special Directions for examining Pearlash and Soda.

To estimate accurately the commercial value of pearlash and soda, we must determine their amount of water, and the quantity of the carbonated alkali. In the first place, it is, however, requisite to ascertain whether they contain any caustic alkali, sulphites or hyposulphites, sulphurets or earthy carbonates, in order that the injurious influence which they would have on the result of the examination may be obviated.

1. Carbonates of the Alkaline Earths. A sample of the pulverized potash of soda is treated with hot rain-water; it should dissolve entirely; if a white powder remain behind, which effervesces with acids after edul coration, it will indicate the presence of carbonate of lime or carbonate of magnesia. In this case, the weighed sample must be treated with hot rain-water, the solution filtered, the residue well washed, and what has passed through, after having been somewhat evaporated, is brought into the bottle A.

2. Sulphites and Hyposulphites. These salts occur only in soda, never in potash. Their presence is most readily detected by coloring about two ounces of dilute sulphuric acid reddish-yellow with some chromate of potash, and then adding some of the soda to be tested, with this precaution, however, that the liquid always remains acid. If the reddish-yellow color is converted into green, then the above salts are present. Sulphuret of sodium gives rise to the same change of color, but wherever this is found, it may be admitted with certainty that hyposulphite of soda is also present. The alkaline sulphurets are most easily detected, by moistening the potash or soda with a solution of common (sesqui) carbonate of ammonia. When they are present, sulphuret of ammonium is given off, which is easily recognized by its smell, and its property of blackening paper moistened with