The pyrometer with its contained water was then just equal in heating capacity, while the temperature was not above 38° F. to two pounds of cold water. The two instruments were sensibly alike, but were numbered No. 1 and No. 2, and at each observation the one used was noted. The process of preparation and testing appears long and tedious, and is indeed somewhat so; but the instruments once well made are durable, convenient in use, and with care reasonably accurate. Compared with mercurial thermometers between 212° and 600° F., I believe them to be much more accurate, although less convenient. For a range of temperatures from 212° to 900° F. they are certainly more trustworthy than anything save an air thermometer of suitable construction; and for all temperatures from 800° to 900° F. up nearly to the melting point of platinum they are without a rival, so far as I know. For some situations the ball can best be inserted in the fire or other situation where an observation is desired, and withdrawn for immersion by means of long, slender tongs, with jaws resembling bullet moulds. A word about the melting point of platinum. My balls certainly began to melt below 2,950° F., but I am by no means sure that they do not contain any silver, although their specific gravity gives assurance that they are at least nearly pure.--_Franklin Journal_. * * * * * LOCOMOTIVE PAINTING. [Footnote: A paper read before the Master Car Painters' Association, Chicago, September, 1883.] By JOHN S. ATWATER. The subject of locomotive painting has been pretty well discussed at the former meetings of the association, and we have heard many excellent suggestions regarding the use of oils, mineral paints, and leads from gentlemen of long experience. But as the secretary has invited a display of my ignorance I will endeavor to explain as clearly as possible the methods I pursue, which, though not new or original, have been productive of good results. If time enough can be had we can prime with oil alone, or in connection with the leads or minerals, and be sure of durability; but in these days of "lightning speed," "lightning illuminations," and "lightning painting," we must look about for something with "chain lightning" in it, which, unlike the lightning, will remain bright and stick after it strikes. We all have to paint according to the time and the facilities we have for doing the work. The scale on iron or steel is the only serious trouble which the painter has to contend with. Rust can be removed or utilized with the oil, making a good paint, but unless time can be given it is better to remove the rust. If possible let tanks get thoroughly rusted, then scrape off scale and rust with files sharpened to a chisel edge, rub down large surfaces with sandstone, and use No. 3 emery cloth between rivet heads, etc., then wash off with turpentine. This will give you a good solid surface to work upon.