Of the Temperature of Steam at different Pressures în Atmospheres. To PREVENT SPONTANEOUS COMBUSTION-It is a fact better ascertained than accounted for, that fixed oils, when mixed with any light kind of charcoal, or substances containing carbon, such as cotton, fax, or even wool, which is not of itself inflammable, heat by the process of decomposition, and after remaining in contact some time, at length burst into flame. This spontaneous combustion takes place in waste cotton which has been employed to wipe machines, and then thrown away and allowed to accumulate into a heap. We have known an instance of the kind in & manufactory for spinning worsteds, where the waste wool, or "slubbings," as it is termed in Yorkshire, was thrown into a corner and neglected. It then heated, and was on the point of bursting into flame, when the attention of the workmen was directed to the heap by the smoke and smell. In cotton mills the danger exists in a still greater degree, and it is believed that the destruction of many cotton factories has been occasioned by this means. The cause of this peculiar property of fixed oils deserves more attention than has hitherto been paid to it. in Inches of Mercury, Of the Elastic Force of Steam, and Corresponding Temperature of the Water with which it is in Contast.. of Water. Of the Force and Temperature of Steam în Atmospheres. 3 TO WRITE ON SILVER WITH A BLACK WHICH WILL NEVER go off.— Take burnt lead and pulverize it. Incorporate it next with sulphur and vinegar, to the consisteney of a painting color, and write with it on any silver plate. Let it dry, then present it to the fire 20 as to heat the work a little, and it is finished. TABLE Of the Heating Power of various Combustible Substances, exhibiting the utmost Quantity of Water evaporated by the Given Weights, and the smallest Quantity of Air capable of producing Total Combustion. TO ESTIMATE DISTANCE --Observe how many seconds elapse between a flash of lightning and the thunder, and multiply them by 1142, the number of feet sound travels in a second, the product will be the distance in feet. The same process may be applied to the flash and report of a gun, or any other sound, provided we can ascertain the time at which it is produced, and the interval that elapses before it reaches the ear.. Illustration. Saw a flash of lightning five seconds before I heard the thunder: required the distance. 5 x 1142 3 × 1760 43 mile distant. 13281 2 In the absence of a watch, the pulsations at the wrist may be counted as seconds, by deducting one from every seven or eight.. {tt. PRISMATIC DIAMOND CRYSTALS FOR WINDOWS-A hot solution of sulphate of magnesia, and a clear solution of gun arabic, mixed together. Lay it on hot. For a margin er for figures, wipe off the part you wish to remain clear with a wet towel PERFECTLY BLACK HARD, GLASS.-Plain paste, 600 parts ;; zaffre, 3 parts; manganese, 3. parts,;, iron, S. parts." |