THE DANCING FOUNTAIN. To the Editor of the Chemist. SIR,-I believe you English are so satisfied with yourselves, that you never inquire into the knowledge of others, and are consequently more ignorant of the discoveries and amusements of other people than any other nation on the face of the earth. I see by an early Number of The Chemist that one of your great philosophers amused his pupils in Edinburgh, by exhibiting to them a hollow brass sphere balanced on a jet of water, "and made to play up and down in a very striking manner,' as a novel and curious experiment. Sir, this has been practised time out of mind in my country, which is Germany, and in Holland, and in a much more amusing manner than that described by the Professor. You know, Sir, that fountains, or what you call jets d'eau, are very common on the Continent, and there it is the practice to have them in our gardens, and within little temples, and when one is found in such a convenient situation, our boys and girls know how to amuse themselves in the manner your Professor taught his pupils. See No, XI, of Chemist, They take pieces of cork, which they cut into various shapes, like the figure I send you, which is the representation of one that I made when I was myself a boy, and they either paint them or clothe them lightly. Within what you call the seat of honour a hollow sphere or ball, made of very thin copper or brass, is fixed, and these little figures are then placed over a perpendicular jet d'eau, and there do they dance and turn round like what you call " merry go mads." Your Professor who taught this to his scholars, as a novel experiment, is known to have been a great. traveller, and I have no doubt that he has seen, a hundred times, little figures dancing on the top of a stream of water, both in Germany and Switzerland. I hope, Sir, that you will give insertion to this letter, that the boys of my country may have the honour which is due to them for having forestalled the English philosophers. I am, Sir, Your very obedient humble servant, EIN DEUTSCHER. P.S. If you insert this communication I shall perhaps send you an account of some other of our boys' tricks. The Editor will be happy to receive the communications of his German correspondent; but he must observe, that he is not aware that Professor Leslie exhibited this experiment as a novelty, but only as an illustration. ANALYSIS OF SCIENTIFIC JOURNALS. (Continued from p.343.) THE TECHNICAL REPOSITORY FOR AUGUST. WE should not have taken any notice of the Technical but for one paragraph. Mr. Gill states, that "Government has given orders for the construction of no less than twenty-four steam engines, each of the power of forty horses." "We are truly glad to hear," he adds, "of this public spirited conduct on the part of Government, and trust that it may lead to a still further encou ragement on its part of our other important national inventions, such as the Hydraulic Press, &c. &c., and thereby obviate the necessity of seeking a market for them in foreign parts." Our readers will probably require to be informed that Mr. Gill is an opponent of the wish entertained by our machinists and iron manufacturers, to get the best and most extended market possible for the produce of their labour; and he penned the above paragraph, with a view of weakening, by holding up the encouragement they receive from Government, their claims to have those laws repealed which now impede the free exercise of their industry. In point of fact, however, the Government has ordered these en gines from no public spirited motive. It has, at length, found, that the service of the post office, in keeping up a regular communication with different parts of our own and foreign countries, can be best performed by steam vessels. A certain number has, therefore, been ordered, and they are now building in his majesty's dock yards. The steam engines are for these vessels, and the Government displays no more public spirit in ordering them, that has been evinced by the Edinburgh and Margate steam packet Companies, in ordering almost an equal number. Having thus shown the nonsense of Mr. Gill's unnecessary praise, we shall now say a word or two on the further nonsense of wishing the Government to encourage our national inventions, and thereby obviate the necessity of seeking a market for them in foreign parts. If the Government needs such machines for any useful purpose, it can get them nowhere but from our own manufacturers; and so far we hope that it will not be so egregiously silly as not to order them. But every one of these engines, and every other of its expenses, is paid for by taxes on the people, and we ask Mr. Gill if he would have the people taxed for the benefit of Messrs. Boulton and Watt, who are already very rich, or for the benefit of any other maker of engines? To order engines from them, unless they are wanted, like these for the steam post-office packets, for a profitable purpose, is only employing the money and industry of the people in putting up machines, that will cost a still further sum to keep them in repair, or will go to decay. A market for our goods in foreign countries is precisely what numerous treaties have been made to obtain, and the necessity for which no rational man seeks to obviate. Nature has bestowed on different countries different climates and different productive powers, and on their inhabitants different capacities. She has scattered her benefits profusely in all parts, but not bestowed on any two parts au exactly similar blessing. The necessity, therefore, which Mr. Gill wishes to obviate, of one country finding a market for its produce in other countries, arises from the nature of things, and if obviated, would leave no two countries of the world any means of assisting each other, or cultivating mutual friendship. Man would then be every where a savage. 4 "A bounteous plenty is the robe, And trade the golden girdle of the globe." When we find a market for our commodities in foreign parts, we receive in exchange from their inhabitants some of the products of their industry, which are to us of more value than those things we gave for them. This is what Mr. Gill would do away. He wishes that one part of the people should be taxed, to the great increase of custom and excise officers, impeding locomotion and industry, begetting numbers of crimes, such as false oaths and smuggling, with all its horrors of resistance and murder, for the benefit of some machinists, rather than that they should be allowed to exchange the produce of their labour with some men living across the English Channel, for something they regard as more valuable. And this is the learning and wisdom which Thomas Gill, Chairman of the Committee of Mechanics, &c. &c. labours to impart to the public. We hope the youthful readers of the Chemist will never adopt such ab surd prejudices, and will never swell with their voices that antihuman cry, which a few interested and unthinking men raise to check, though by inflicting privations and misery on ourselves, the prosperity of others. DISCOVERY OF A MINE OF QUICKSILVER AT IDRIA, IN CARNIOLA. A Carniolean peasant, who drove a small trade in wooden vessels, was in the habit of groping his way into a recess of the mountains, at that time entirely covered with wood, to procure materials for his tubs and pails, which he sometimes finished on the spot. He had placed some pails over night in a small pool in a rivulet which flowed from the mountain, for the purpose of seasoning them. To keep them under water, he put into them a quantity of sand, taken from the bed of the stream. In the morning he was scarcely able to lift one of his pails out of the water. He could ascribe this only to the weight of the sand, and sand so heavy was to him a phenomenon, and he carried some of it to the pastor of his village. The latter, suspecting what might be the reason, sent some of it to the Imperial director of the mines, and on examination, it was found to contain half its weight of quicksilver. The whole of the department of Idria was immediately declared a domain of the crown, but the mines were first worked by private adventurers, on leases; and the miners still preserve various traditions of the difficulties these speculators had to encounter. Shafts were driven deep into the solid rock, but no quicksilver was found; patience and money were wearing out, and the speculators gradually drew back, leaving it all at last in the hands of one more sanguine and persevering than the rest. He too hoped and laboured in vain; ruin came, not quicksilver, and the destitution into which he had plunged his family by his unsuccessful adventure, brought him to the grave. His widow was compelled to give up the operation, but the workmen declared they would still make an attempt for the family of him who had so long given them bread, and continued their search fourteen days longer without wages. The fourteenth day arrived, but no quicksilver was found. Towards the afternoon, as the workmen, who had been annoyed all day long by sulphurous vapours, and a more uncomfortable atmosphere than usual, were about to give up their task for ever in despondency, and prepare to celebrate above ground the festival of their patron saint, of which this happened to be the eve, a shout from the lowest part of the shaft announced that the deeply concealed vein had at length been dragged from its lurking place. The saint was neglected, and the mercury pursued. It was soon ascertained that the labour and expense of years were sure to be amply repaid. The revived widow prudently sold her right to the government, and since that period, now 400 years ago, Idria has not ceased to pour its thousands into the Imperial treasury. 1 REPLY TO CASTIGATOR. August 14th. HAD I known, Mr. Editor, when I offered for insertion my two Queries on Onion Juice and Tallow, that I had so critical a palate to please as that of “ Castigator," I might certainly, instead of presenting them together, have served them up in two courses; but as I did not wish to give you unnecessary trouble, I thought it best to act as I did. In what manner they have been so strangely united," as Castigator says they are, I cannot conceive; since, when I last saw them in your pages, they were perfectly distinct and separate, although not half a mile apart. It appears to me very singular that this gentleman should not be able to foresee 66 every future "application of fat and onions," considering the great abilities which he must necessarily possess, to qualify him for the office of castigator and corrector of opinions. My intelligent respondent asserts, that onions may be kept from harvest to harvest; he might have added, so may potatoes; but can he say that they will retain all their original strength and good qualities? He also kindly informs me, that fat is a general name for several kinds of animal oil, while tallow is a particular species of fat; but unfortunately he has forgotten to describe the " particular species," which, together with the method of separating its acid and membranous parts, is all the information I require, since I cannot procure it at the tallow-chandler's sufficiently pure my purpose. As I am accused of want of precision in my mode of stating these two queries, I should feel obliged if Castigator will put them into the precise form and attitude necessary to elicit the information required; and I repeat, that the information I want, is 1st. Whether there is any mode With many thanks to you, Sir, for your kind and early insertion of my queries, and to Castigator for his kind and early attention to them, I remain, Your obliged and obedient servant, A CONSTANT READER. The Editor thinks he will do right to put a stop to this controversy by answering the queries himself. He has never heard of any extract being made from onions for preservation. Squills, sea onions, and all such things, which are preserved many years, are dried, and are infused when wanted. Flower roots, analogous in their nature to onions, are preserved many years. As common onion is of the same genus, he supposes this method would also answer with them. He knows that if care is taken of them and they are dried, they are as good at the next harvest as when taken out of the ground. They are preserved by being slightly kiln-dried, or by having the root and top seared with a hot iron. At the same time, he will readily insert any more satisfactory answer to his Correspondent's query. Tallow or fat may be obtained pure by cutting suet or hogs'-lard in small pieces, washing it well in water, and mechanically separating the membranous parts. It is then to be melted in a shallow vessel with a small quantity of water, and kept melted till the water is completely evaporated. It is white, tasteless, and nearly insipid. Mr. Chevreuil has proved that this fat may be again separated into distinct substances, one of which is fluid and the other solid, at the temperature of the atmosphere. In The Chemist, No. IV. the mode of separating the two has been described; the solid part, which is called stearine, may also be thus procured: - Hogs'-lard, purified as completely as possible from foreign matter, is to be dissolved in boiling alcohol; when this cools it deposits white crystalline needles, which are stearine. Repeating the process, the whole of the lard may be dissolved, and the crystallized stearine is afterwards again dissolved in alcohol, and once more allowed to crystallize, by which it is obtained nearly pure. The method described in our No. IV. will also give the stearine pure. This will probably suit our Correspondent's wishes.-ED. TO CORRESPONDENTS. A. Z., A Stone, and Philo-Chemicus, all came too late for the present Number. Observator is intended for publica tion. *Communications (post paid) to be addressed to the Editor, ci the Publishers'. London: Published by KNIGHT and LACEY, 55, Paternoster-row. Printed by B. Bensley, Bolt-court, Fleet-street. TO DECOMPOSE WATER BY GALVANIC ELECTRICITY. (From a Correspondent.) To effect this it is quite necessary that your correspondent should provide himself with a galvanic battery, or he may make a voltaic pile, one of which I see has been already described in The Chemist, at page 172, No. XI. The wires should be of platina, as with other metals all the oxygen of the water will combine with the wire, and the hydrogen gas alone be disengaged. To merely effect the decomposition without procuring the products separately, a glass tube must be procured, and after being nearly filled with water, must be corked up at both ends. The two |