MESSES. EDITOES:—I notice on page 297 of the present volume of the SCIENTIFIC AMERICAN, some remarks upon electric light. Electricity is very troublesome in our works at times, particularly in the worsted department. When the wind is strong in the northwest, with clear sky and windy, it is almost impossible to keep the wool in its place without much open steam to damp the air in the room. The belts that pass through the room are so highly charged that, to stand under a belt 12 inches in width, running 3,500 feet per minute, by holding one hand up -within half an inch of the belt and extend the other hand to a gas burner, it will light from the end of the man's fingers as quick as from a lighted torch. Is there any danger from fire through this agency in th mills ? In what way can I try experiments in a small way to produce light from this ? Please to give me your views upon the above. WATCHMAN SMITH, Agent. Manchester Print Works, N. H., Nov. 27, 1860. [We hava seen Iamp3 in woolen, manufactories kept constantly burning under the rolls, as they came from the cards, to prevent the accumulation of electricity. We do not believe the electricity generated in your mill will be found sufficiently constantto serve for lighting the rooms, but it you wish to try it, the proper plan would be to distribute insulated wires, such as are used for making helices for electro-magnets, with their points near the belts, rolls, &e., where electricity is generated, and then collect them all into one wire to be connected with a mercury hour glass, such as is described on page 297 of our current volume. THE MINERALS IN OUR BODIES.In the body of a man weighing 154 pounds, there are about 7 pounds of mineral matter, consisting of phosphate of lime, 5 pounds, 13 ounces ; carbonate of lime, 1 pound ; salt, 3 ounces, 376 grains ; peroxyd of iron, 150 grains ; silica, 3 grains. Making 7 pounds, 5 ounces and 49 grains, with minute quantities of potash, chlorine and several other substances. The rest of the system is composed of oxygen, hydrogen, nitrogen and carbon ; 111 pounds of the oxygen and hydrogen being combined in the form of water. Though the quantity of some of these substances is very small, it is found absolutely essential to health that this small quantity should be supplied ; hence, the importance of a variety of food. If we furnish Nature with all the material required, she will select such as the system needs, and always just in the proper quantities.