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For some situations the ball can best be inserted in the fire or other situation where an observation is desired, and withdrawn for immersion by means of long, slender tongs, with jaws resembling bullet moulds.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.