is turned on, the more the top of the chimney is opened, and the more air admitted. This would do very well if gas were supplied every where at an equal pressure; but as the pressure is different in almost every situation, in some places it is necessary to open the supply cock entirely to obtain a very small flame, while in others a very large one is produced by opening it a very little; consequently, in the first case we should have the chimney entirely open, and so a large quantity of air admitted to a very small quantity of gas; while in the second, the chimney would be nearly stopped, while a large quantity of gas would be admitted into it, the consequence of which would be that the flame would smoke very much. We ought, however, to state, that the burners which are sold with this apparatus are remarkably good, and may be employed with great advantage without the regulator. They are made, not by drilling holes through a piece of metal, as in a common burner, but the whole top of the burner is turned out so as to form a slit about one-eighth of an inch wide; a ring of metal is then turned to fit this slit accurately, and the outer edge of it is finely milled, so that when it is put in its place in the slit, the milling forms a series of very fine holes. The advantages of this are two; first, that a mill can be made much finer than any hole can be drilled; secondly, that it is much more easily cleaned, all that is requisite, if they become dirty or corroded, being to take out the ring and well brush its milled edge. Another invention, in which the fact that gas lamps have ordinarily too much air in proportion to their carbon, is that of Mr. Low; the defect being remedied, not by decreasing the supply of air, but by increasing that of carbon. This is done by passing the gas through a vessel filled with naptha, the vapour of which coming over with the gas, increases greatly its quantity of carbon. We come now to the consideration of the most perfect lamp (theoretically speaking) which has ever been invented; we mean the ventilating lamp of Mr. Faraday, a patent for which was taken out by his brother in 1843. It may not be uninteresting briefly to relate a few of the circumstances which led to the invention, and which were detailed by the inventor in an admirable lecture delivered at the Royal Institution. It seems that he was applied to by the authorities at the Trinity House to remedy some very great defects in their lighthouses, the first being the inconvenience experienced by the men who have to attend to the lamps, in consequence of the large quantity of foul air given out from them into the small room which constitutes the lantern of the lighthouse; the second, the condensation on the windows of a large quantity of water (also produced by the lamps), which, in cold weather, becomes frozen, and renders the lights inside much less visible than they ought to be. He found, on examination, that any attempts to get rid of the foul air by simply making a way for it to escape at the top of the lantern, would be useless, as the only thing which gives it an upward tendency is the circumstance of its being hot and rarified, so that before it can reach the top of the lantern it becomes cooled, and descends into the room. In order, then, to carry off the vapour, he placed a tube immediately over the lamp, rather smaller than the chimney, the top of which it just enters, the other end of the tube is carried out at the top of the lighthouse. This tube, being made of metal, soon becomes heated, and so serves to keep the foul air hot until Fi 1 it escapes out of the top of the tube. To prevent the wind blowing down this tube, and extinguishing the lamp, which in the high situations usually occupied by lighthouses it would be apt to do after it comes into the open air, it is formed into the shape shown at fig. 1, where it will be seen that any air blowing in at the top encountering the upward current of foul air, will be driven out at the funnelshaped holes in the lower part of the tube, instead of going down to the lamp. Here, then, is very perfect ventilation, but a very ugly appearance: to do away with this, so as to render the invention applicable to lamps for drawingrooms, &c. was the next object, and, after a variety of experiments, Mr. Faraday was led to the form shown in fig. 2, in which a represents the supply pipe for gas, b the cock, e an ordinary argand burner, f the tube for carrying off the products of combustion, g a gallery formed on this tube to carry the chimneys d and e, there being an opening through the gallery into the tube f, opposite the space between the glasses d and e; the top of the glass e is covered with a plate of mica, in frame, to prevent any of the products of combustion passing out in that direction. Fig 2 Now, it is manifest that the only way in which any vapour can escape from this lamp, is in the direction shown by the arrows, viz. out of the top of the inner glass, down between the two chimneys, and so through the tube f, into the outward air: this direction, however, it cannot take, unless a draught is first established in the tube f, which is done by holding a lamp under the bend of the tube f, at h, so as to heat the air it contains, and cause it to rush up the ascending part of the tube; after the draught is once established, the supply of hot air from the lamp is sufficient to keep it up, unless it has to go a very long way, when it is better, if possible, to carry it into a chimney, the draught of which will very much assist that of the lamp. In the drawing here given, the supply pipe and the exit tube are made at a short distance apart, in order that they may be better seen, but they may of course be placed quite close together, so that the one enters and the other leaves the room through the same hole, all appearance of the exit pipe being thus avoided. The great inconvenience in these lamps is, that, should the person employed to light them neglect to warm the bend of the tube f, the chimney will be sure to be broken, by the flame being driven against it. Their advantages are obvious, namely, the getting rid of all the products of combustion, and also burning the gas with a greatly diminished supply of air, which renders their employment very economical, and their light more agreeable. One fact was elicited during the progress of the invention of these lamps, viz. that those large glass bells, with a tube coming out of the top, hung at some distance above gas lamps, for the purpose of carrying off their vapours, are of no use, as they so cool them, that they descend again into the room. We now take our leave of this subject, trusting that the principles we have endeavoured to lay down may be of some assistance to those who wish to combine a good light with economy, and an absence of as much deleterious vapour as possible. MARCELLUS; OR, THE OLD COBBLER OF THE COTTAGE. (Concluded from page 99.) He turned the louis-d'ors over and over, shook them in the palm of his hand, and then carefully folded them up again in the paper. He felt no inclination to sleep, but looked, first at the road which the traveller had taken, and next at his cottage. Bertha, in her turn, was at the window, looking round for her husband. He called to her, and made signs that she should come to him. What are you doing there? cried she. MARCELLUS. A noble find, Bertha! look at this paper. MARCELLUS. Yes, certainly I believe that they are double louis. BERTHA. Double-one, two, three, four; why then there are eight louis— and what a little room they go into! and is this cross gold or copper? MARCELLUS. I believe it is gold, and the chain also. BERTHA. My God, my God, what a treasure! it is as if an angel had placed it here for us. It is your prayer that has obtained this find. God has sent food to the ravens. Now, we are rich for the present, and for a long time to come! Here, Marcellus, with one of these pieces we will both have clothes, and good warm ones too; with another, we will lay in some wheat; with the third some furniture and utensils; and with the fourththere is not enough for a cow? No; we must not be too ambitious; we will keep the fourth, and the cross, for accidents. If we should fall ill, for example. You laugh, Marcellus, now; and truly I think so too, if we had only MARCELLUS, interrupting her with vivacity. Good Bertha, I laugh at the manner in which you dispose of what does not belong to us. BERTHA. What! what do you say? have you not found it? do you even know who has lost it? neither gold nor money have marks, but belong to those who find them. MARCELLUS. But, Bertha, I do know to whom they belong. MARCELLUS. They belong to a traveller who rested himself at this place not a quarter of an hour ago. I saw him from our window. He opened a wallet, and spread out a piece of cloth; and it was then that this packet fell upon the grass. BERTHA. He must have a great many of these louis, since he pays so little attention to them, and could lose them in such a manner to him, the loss is a trifle; and to us, the find is our all. MARCELLUS. You are right, Bertha, it is our all, for it is able to save or lose our souls. We have but a few years to live, and shall we burden our consciences with the weight of these eight louis? Do you believe that they would do us any good? you deceive yourself; we shall be a hundred times less happy than we are, if we yield to the temptation of keeping them: we should have a better bed, and we should not sleep more soundly; we should have better clothes, and we should no more dare to go to church in them than in our rags; and when the day shall come in which we are to give an account of our actions, what excuse should we offer for this? Our extreme poverty? but that is an additional motive for being honest, because we are so often tempted not to be so, and because we must not part with the only treasure that is left us-our peace of conscience. Take courage, Bertha; we shall not die with hunger: look around, and see all these fields covered with corn; the harvest is coming, and we shall glean. The judge is kind to us, and see what a fine crop he has got! I wager that he will even give us two or three sheaves; and the parson too: and that will be better than this gold, which does not belong to us. BERTHA, sighing. Yes, for food; but where shall we get any thing for clothes? MARCELLUS. Heaven will provide them. Have I not just read to you, that it clothes the lilies of the field, and that we must take no thought for the morrow? The traveller will perhaps give me a reward. I shall not deserve it, for so simple an affair; but if he should give me enough to buy you a table-cloth, Bertha, I will accept it willingly, and gratefully. BERTHA. It is very well; but where will you find him again? MARCELLUS. I shall instantly cut across the fields. You know that the road makes a great circuit on account of the river: one gains more than a quarter of a league by this path, and I trust to find him below. BERTHA. I hope you will; but if you should not find him? MARCELLUS. Oh! then, dear wife, in spite of my repugnance, I shall resolve on BERTHA. Keeping the eight louis-will you not? MARCELLUS. Begging-to support me on my journey to the city, and to enable me to pay for an advertisement which I will put into the paper. Go, look for my stick, Bertha, and do not make yourself uneasy if I am not back immediately; only make haste. Bertha ran: she was ashamed at having misunderstood her husband. This last determination of his had rekindled in her heart those virtuous sentiments which the sight of the gold had but obscured for a moment. She returned immediately with the stick. Take it, said she, and go as quickly as you can. I wish that this vile gold, which has drawn me into sin, were no longer in our hands. Marcellus set out; but his legs, stiffened by age, and by his sedentary occupation, did not obey his heart, and he walked with difficulty. The wind blew through the locks of his white hair, and the rags of his poor clothing. Bertha followed him with her eyes to the top of the hill, and wished that she could hasten his progress by looking after him. He will miss his traveller, said she, and the poor old man will kill himself with walking six long leagues to the city. But I am beside myself; it is I that ought to go. I am six years younger, and I am much stronger. Come; he goes so slowly that I shall soon catch him. And now behold Bertha, at more than sixty-five years of age, fancying herself young in comparison with her husband, and actually running as if she were but thirty! She overtook him at the end of the field, and held him by the arm. Sit down here, said she, and let me go in your stead. MARCELLUS. No, my good Bertha; you have not seen the man, you will not know him again, and you will perhaps meet with some knave, who will tell you that the money is his. vapours, are of no use, as they so cool them, that they descend again into the room. We now take our leave of this subject, trusting that the principles we have endeavoured to lay down may be of some assistance to those who wish to combine a good light with economy, and an absence of as much deleterious vapour as possible. MARCELLUS; OR, THE OLD COBBLER OF THE COTTAGE. (Concluded from page 99.) He turned the louis-d'ors over and over, shook them in the palm of his hand, and then carefully folded them up again in the paper. He felt no inclination to sleep, but looked, first at the road which the traveller had taken, and next at his cottage. Bertha, in her turn, was at the window, looking round for her husband. He called to her, and made signs that she should come to him. What are you doing there? cried she. MARCELLUS. A noble find, Bertha! look at this paper. BERTHA. Jesus, Maria, it is money-gold-is it not? MARCELLUS. Yes, certainly I believe that they are double louis. BERTHA. Double-one, two, three, four; why then there are eight louis— and what a little room they go into! and is this cross gold or copper? MARCELLUS. I believe it is gold, and the chain also. BERTHA. My God, my God, what a treasure! it is as if an angel had placed it here for us. It is your prayer that has obtained this find. God has sent food to the ravens. Now, we are rich for the present, and for a long time to come! Here, Marcellus, with one of these pieces we will both have clothes, and good warm ones too; with another, we will lay in some wheat; with the third some furniture and utensils; and with the fourth— there is not enough for a cow? No; we must not be too ambitious; we will keep the fourth, and the cross, for accidents. If we should fall ill, for example. You laugh, Marcellus, now; and truly I think so too, if we had only MARCELLUS, interrupting her with vivacity. Good Bertha, I laugh at the manner in which you dispose of what does not belong to us. BERTHA. What! what do you say? have you not found it? do you even know who has lost it? neither gold nor money have marks, but belong to those who find them. MARCELLUS. But, Bertha, I do know to whom they belong. MARCELLUS. They belong to a traveller who rested himself at this place not a quarter of an hour ago. I saw him from our window. He opened a wallet, and spread out a piece of cloth; and it was then that this packet fell upon the grass. BERTHA. He must have a great many of these louis, since he pays so little attention to them, and could lose them in such a manner to him, the loss is a trifle; and to us, the find is our all. MARCELLUS. You are right, Bertha, it is our all, for it is able to save or lose our souls. We have but a few years to live, and shall we burden our consciences with the weight of these eight louis? Do you believe that they would do us any good? you deceive yourself; we shall be a hundred |