from the cylinder of a pressure lamp, flows up the standpipe and overflows at the top, descending by another pipe surrounding the stand-pipe to a cistern below the burner. A glass thimble is screwed on to the top of the regulator, through which the state of the flow can be observed. The necessary adjustments of supply are made from time to time by the ordinary regulating-valve placed in the supply-pipe below the burner. The tops of the inner and outer tubes of the stand-pipe are rendered telescopic by a piece of pipe fitted to and sliding on them externally; by means of these sliding pieces the flow of the lamp can be altered at any time so as immediately to adapt it for burning any descrip. tions of hydrocarbon. As the invention appears to me to be of importance for regulating the flow of all lamps used for burning mineral oils, I have had it provisionally protected. "As it is found to be necessary in burning paraffine that its level in the wick-case be considerably below the top of the burner, it may reasonably be expected that the tips of the burners will be destroyed by the heat of the flame much sooner than with burners consuming colza-oil, where the latter is constantly overflowing the burners and keeping them cool. I have provided for this increased destruction of burners by fitting each with removable tips, as shown on Removable tips. the accompanying drawings. With this arrangement, and by keeping a supply of spare tips at each station, the tips of the burners may be renewed at any moment by the lightkeeper in charge, thereby avoiding the necessity for returning the burner to the workshops for repairs. "The following are the mean results of several six-hour experiments. Comparative "The above experiments with this lamp, as now improved, cost of colza and show the comparative cost of light produced by colza-oil paraffine. and paraffine when consumed in a first-order burner to be as 38 to 15. From these results it will be observed that the superiority in illuminating power of the paraffine over the colza oil is much greater when consumed in the Argand burner than when consumed in the large four-wick burner; consequently the contrast between the cost of light produced by the two oils is greater when the oils are consumed in the Argand burner than when consumed in the four-wick burner. "Further experiments were made for ascertaining the relative illuminating power of the paraffine and colza lamps during the time required at a light-house on the longest winter night. Each lamp was kept burning for sixteen hours without any trimming of the wicks, and the following are the photometric results of several experiments: Deductions. sity. "From these results it is apparent that the paraffine lamps will burn throughout the longest winter night in this country without any trimming of the wicks, and give during Sustained inten- this time a light of nearly uniform photometric value. At the end of sixteen hours the illuminating power of the Argand lamp, burning paraffine, was only 10 per cent. less, and in the four-wick lamp only 10.7 per cent. less, than at the commencement of the trials, while the illuminating power of the lamps burning colza-oil gradually decreased soon after the commencement of the trials, and at the end of sixteen hours the illuminating power was reduced 15.1 per cent. in the Argand burner, and 25.6 per cent. in the four-wick burner. State of wicks. "At the termination of these trials the wicks of the paraffine lamps were not much fatigued; the tips were charred Colza lamp. only one-eighth of an inch in depth, and to all appearances the lamp was fit for burning many hours longer. The wicks of the colza-lamp were much distressed; they were charred five-sixteenths of an inch in depth, and evidently nearly worn out; trimming would have been absolutely necessary if burned for three or four hours longer. "In conclusion, it may be generally stated as the result of the lengthened experiments which have been made at this House with paraffine as an illuminant for light-houses"1st. The cost of light is 72.7 per cent. less when produced Comparative by the Argand or single-wick lamp, and 60.5 per cent. less when produced in the first-order or four-wick lamp, than colza oil. "2d. The lamps burning paraffine will give a light of more uniform illuminating power throughout the night, without trimming, than the lamps burning the colza-oil. cost. Paraffine light more uniform. "3d. The lamps burning paraffine are more readily ignited; Paraffine lamps they burn with greater certainty, and require less attention than easier to tend. lamps burning colza-oil. "4th. The lamps burning paraffine may be arranged for Increase of increasing the power of the light when the state of the weather power possible. requires it, as is now done with the electric light and coal-gas. 5th. Paraffine can be stored and used at light-houses with Paraffine may safety, provided that ordinary care is used. be stored with safety. "I am, &c., "JAS. N. DOUGLASS." The tables given in the foregoing report showed 1st. That light for light with a first-order lamp, the cost Cost with firstof the paraffine was about one-half that of the colza light. 2d. Light for light with the fourth-order lamp, the cost of paraffine was about one-fourth that of colza. order lamp. with fourth-order lamp. above. These results were confirmed by a comparison of the fig ures in the following table of results obtained by Dr. Mac- Confirmation of adam, scientific adviser of the board of commissioners of northern (Scottish) lights, Mr. Douglass, engineer of the Trinity House, and Professor Tyndall, scientific adviser of the Trinity House, by quite separate and distinct experiments. Comparative statement of experiments for testing the values of colza and paraffine as illuminants for light-houses. Result of improvements made The foregoing tables were among the earliest results of experiments with paraffine oil and petroleum. The improvements made by Mr. Dougiass from time to byr. Douglass. time in lamp-burners have resulted in what is apparently a perfect light-house lamp, which can hardly be surpassed in economy and efficiency except by the supply of pure oxygen to the flame. or. Details of lamp. Burner-tips. Exterior deflect Each of the Douglass lamps now made for the English light-houses has 1st. A series of burner-tips so constructed that they may be removed when burned out, instead of substituting new burners, as is done under the old system. These tips," which slightly compress the wicks, give to them a perfectly cylindrical form, and their exterior surfaces being slightly conical, the air from below is sent directly into the flame without danger of forming eddies where the gases burn imperfectly. Interior deflect- 2d. A curvilinear perforated "button," (interior deflector,/ which sends the interior current of air into the flame. 3d. An outer "cone," (exterior deflector,) by which a second current of air is thrown into the flame at its most advantageous zone. or. Outer air-current. 4th. A space between the cone and the chimney, by which a third or outer air-current is produced. Colza. Parafine. This air-current is injected into the flame above that admitted by the "exterior deflector," and is for the purpose of increasing combustion. A portion of this current being drawn up along the surface of the chimney, prevents the heat from melting or otherwise injuring the glass, in which a milkiness resulting from disintegration sufficient to im pair the light, is found to be produced by long-continued heat. Another result produced by this current is that the base Chimney kept of the chimney is kept at a degree of temperature sufficiently low to admit the removal of the chimney with the naked hand, rendering the use of tongs unnecessary. cool. lery. 5th. An adjustable gallery by which the chimney is raised Adjustable galand lowered at will, it being found that the height of the shoulder of the chimney has a marked effect upon the flame. 6th. Very soft and compressible wicks adopted for this Soft wick. lamp only after many repeated experiments. these inventions. Each of these inventions, some of which were original, Combination of with Mr. Douglass, and some had previously been in use, is considered of importance, but a combination of the whole is essential to produce the remarkable results given in the following table deduced from the most recent experiments of Mr. Douglass and kindly sent me by him since my return to this country: Comparative statements showing the mean illuminating power and consumption of oil with the old and improved light-house burners of the Corporation of Trinity House. Number of wicks : Old concentric burners con- Improved concentric burners con- suming colza. Comparative results of experiments with Mr. Douglass's burn er. |