Various

“ The rate of ordinary chemical corrosion of each metal varied in every different liquid; in each solution also it differed with every different metal. The most chemically positive metals were usually the most quickly corroded, and the corrosion of each metal was usually the fastest with the most acid solutions. The rate of corrosion at any given temperature was dependent both upon the nature of the metal and upon that of the liquid, and was limited by the most feebly active of the two, usually the electrolyte. The order of rate of corrosion of metals also differed in every different liquid. ”

“ I regard this as an error, and as the sign of a warped judgment, for after all man is to us the most important part of nature; but the system works well nevertheless, and the division of labor accomplishes its object. One man investigates nature impelled simply by his own genius, and because he feels he cannot help it; it never occurs to him to give a reason for or to justify his pursuits. ”

“ A warm and wet autumn will subject the fruit to the ravages of a maggot or worm, which eats its way into it. Fruit thus injured falls to the ground prematurely, and the oil made from it is of very bad quality, being nauseous in taste and somewhat thick and viscous. Frost following immediately on a fall of snow or sleet, when the trees are still wet, will irretrievably damage the fruit, causing it to shrivel up and greatly diminishing the yield of oil, while the oil itself has a dark color, and loses its delicate flavor. ”

“ A dust particle is illuminated like any other solid screen, and is able to send a sufficient fraction of light to our eyes to render itself visible. If there are no such particles in the beam—nothing but clear, invisible air—then of course nothing is seen, and the beam plunges on its way quite invisible to us unless we place our eyes in its course. In other words, to be visible, light must enter the eye. (A concentrated beam was passed through an empty tube, and then ordinary air let in.) ”

“ Surrounding all bodies warmer than the air is a thin region free from dust, which shows itself as a dark space when examined by looking along a cylinder illuminated transversely, and with a dark background. ”

“ Aitken has shown that the steam cannot condense until it is highly supersaturated, and that when it does it condenses straight into rain—that is, into large drops which fall. The condensation of steam is a more delicate test for dust than is a beam of light. A curious illustration of the action of nuclei in condensing moisture has just occurred to me, in the experiment—well known to children—of writing on a reasonably clean window-pane with, say, a blunt wooden point, and then breathing on the glass; the condensation of the breath renders the writing legible. ”

“ To avoid peeling and blistering, the paint should be mixed with raw linseed oil in such proportions that it neither becomes too brittle nor too soft when dry. Priming paint with nearly all oil and hardly any pigment is the foundation of many evils in painting; it leaves too much free oil in the paint, forming a soft undercoat. For durable painting, paint should be mixed with as much of a base pigment as it can possibly be spread with a brush, giving a thin coat and forming a chemical combination called soap. ”

“ The best quality of Tuscan olive oil is imported in London in casks, bottled there, and bears the name of the importers alone on the label. There is no difficulty in procuring in England the best Tuscan oil, which nothing produced elsewhere can surpass; but consumers who wish to get, and are willing to pay for, the best article must look to the name and reputation of the importers and the general excellence of all the articles they sell, which is the best guarantee they can have of quality. ”

“ The electrical effect of heating a voltaic couple is nearly wholly composed of the united effects of heating each of the two metals separately, but is not however exactly the same, because while in the former case the metals are dissimilar, and are heated to the same temperature, in the latter they are similar, but heated to different temperatures. Also, when heating a voltaic pair, the heat is applied to two metals, both of which are previously electro-polar by contact with each other as well as by contact with the liquid ”

“ We thus see that when the air in a room is warmer than the solids in it—as will be the case when stoves, gas-burners, etc., are used—things will get very dusty; whereas when walls and objects are warmer than the air—as will be the case in sunshine, or when open fireplaces are used, things will tend to keep themselves more free from dust. ”

“ After linseed oil has been boiled, it becomes a poor varnish; it remains soft and pliable when used in paint, giving way to air pressure from the wood in hot weather, forming blisters. Turpentine causes no blistering; it evaporates upon being exposed, and leaves the paint in a porous condition for the gas in the wood to escape; but all painters agree that blistering is caused by gas, and on investigation we find two main sources from which gas is generated to blister paint—one from the wood, the other from the ingredients of the paint. ”

“ That as the object of wing or screw is to mount upon the inertia of the particles of a mobile fluid, and as the rotation of steamship propellers in water—a fluid of many times the inertia of air—is already in excess of the highest speed heretofore tried in the propellers of moderately successful flying machines, it is plain that the speed employed in water must be many times exceeded in air. ”

“ A wash made of soap, tobacco water, and fresh cow manure mingled to the consistency of cream, and put on early with an old broom, and allowed to trickle down about the roots of the tree, has proved with me a very excellent preventive of the ravages of the borer, and a healthful wash for the trunk of the tree, much to be preferred to the application of lime or whitewash, which I have often seen applied, but which I am inclined to think is not as desirable an application as the potash, or the soda, as this mixture of soft soap and manure. ”

“ I have, however, cleared a room of smoke very quickly with a small hand machine.
It will naturally strike you how closely allied these phenomena must be to the fact of popular science that "thunder clears the air." Ozone is undoubtedly generated by the flashes, and may have a beneficial effect, but the dust-coagulating and dust-expelling power of the electricity has a much more rapid effect, though it may not act till the cloud is discharged. ”

“ A cloud or mist is, in fact, fine water-dust. Rain is coarse water-dust formed by the aggregation of smaller globules, and varying in fineness from the Scotch mist to the tropical deluge. It has often been asked how it is that clouds and mists are able to float about when water is so much heavier (800 times heavier) than air. ”

“ At high temperatures the coat is thick; at very low temperatures it is absent, and dust then rapidly collects on the rod. On a warm surface only the heavy particles are able to settle—there is evidently some action tending to drive small bodies away. An excess of temperature of a degree or two is sufficient to establish this dust-free coat, and it is easy to see the dust-free plane rising from it. The appearances may also be examined by looking along a cylinder toward the source of light, when the dust-free spaces will appear brighter than the rest. ”

“ Many questions and problems, in physics as well as in chemistry, find their solution only with the aid of mathematics and mechanics. It therefore became necessary, through lectures bearing upon the useful branches of mathematics, to supplement the too limited ideas that pupils brought with them on entering the school. Mathematics and mechanics are therefore taught here at the same time with physics and chemistry, but they are merely regarded in the light of auxiliaries to the latter. ”

“ Air holds more water in solution (or suspension) in a warmer than in a cooler degree of temperature; by means of a simple apparatus sun-heated air is guided over sun-heated water, when the air saturated with water is conducted into a cooler, to give up its water again. But water has an influence toward hastening to blister paint; it holds the unhardened woodsap in solution, forming a slight solvent of the oil, thereby loosening the paint from the wood, favoring blistering and peeling. ”

“ Dusty air itself is only a kind of smoke, and it looks bright, and the thicker the smoke the brighter it looks; the blackness is simply the utter absence of smoke; there is nothing at all for the light to illuminate, accordingly we have the blankness of sheer invisibility. Here is a flame burning under the beam, and, to show what real smoke looks like, I will burn also this spirit lamp filled with turpentine instead of alcohol. Why the convention currents were free from dust was unknown ”

“ Now, inasmuch as soft drying paint is unfit to answer the purpose, it is equally as bad when paint too hard or brittle has been used, that does not expand and contract in harmony with the painted article, causing the paint to crack and peel off, which is always the case when either oil or varnish has been too sparingly and turpentine too freely used. Intense cold favors the action, when all paints become very brittle, a fact much to be seen on low-priced vehicles in winter time. ”

“ In such a case the unequally heated metal behaves to some extent like two metals, and the unequally heated liquid like two liquids, and so the thermo-electric pair is like a feeble chemico-electric one of two metals in two liquids, but without corrosion of either metal. If the metal and liquid are each, when alone, thermo-electro-positive, and if, when in contact, the metal increases in positive condition faster than the liquid by being heated, the latter appears thermo-electro-negative, but if less rapidly than the liquid, the metal appears thermo-electro-negative. ”

“ Aitken has indeed suggested a sort of practical dust or smoke filter on this principle, passing air between two surfaces—one hot and one cold—so as to vigorously bombard the particles on to the cold surface and leave the air free.
But we have found another and apparently much more effectual mode of clearing air than this. We do it by discharging electricity into it. It is easily possible to electrify air by means of a point or flame, and an electrified body has this curious property, that the dust near it at once aggregates together into larger particles. ”

“ The season is now at hand when farmers who have light lands, and who may possibly find themselves short of fodder for next winter feeding, should prepare for a crop of millet. This is a plant that rivals corn for enduring a drought, and for rapid growth. There are three popular varieties now before the public, besides others not yet sufficiently tested for full indorsement—the coarse, light colored millet, with a rough head, Hungarian millet, with a smooth, dark brown head, yielding seeds nearly black, and a newer, light colored, round seeded, and later variety, known as the golden millet. ”

“ And when the particles have grown into big ones, they easily and quickly fall. A stronger charge forcibly drives them on to all electrified surfaces, where they cling. A fine water fog in a bell jar, electrified, turns first into a coarse fog or Scotch mist, and then into rain. Smoke also has its particles coagulated, and a space can thus be cleared of it. I will illustrate this action by making some artificial fogs in a bell-jar furnished with a metal point. First burn some magnesium wire, electrify it by a few turns of this small Voss machine, and the smoke has become snow ”

“ I have found, I think, that whale oil soap can be used successfully for the destruction of that insect. It is a very simple thing; it will not hurt the tree if you put it on its full strength. You can take whale oil soap and dilute until it is about as thick as paint, and put a coating of it on the tree where the holes are, and I will bet you will never see a borer on that tree until the new crop comes. ”

“ There is good reason to believe that its inventor will be able to advance our knowledge of the subject by a long and important step; and it is no breach of confidence to add that so far, although the research is not near completion yet, everything seems to confirm the belief that the radiated heat of the moon, instead of forming the principal part of the heat we get from her, is relatively almost insignificant, and that the lunar surface now never experiences a thaw under any circumstances. ”

“ It may be possible to clear the air of tunnels by simply discharging electricity into the air—the electricity being supplied by Holtz machines, driven say by small turbines—a very handy form of power, difficult to get out of order. Or possibly some hydro-electric arrangement might be devised for the locomotive steam to do the work. I even hope to make some impression on a London fog, discharging from lightning conductors or captive balloons carrying flames, but it is premature to say anything about this matter yet. ”

“ The fruit of the olive tree varies just as much in quality as does the grape, according to the species of the tree itself, the nature of the soil, exposure, and climate of the locality where it grows. ”

“ A rod of electric light carbon warmed and fixed horizontally across a bell-jar full of dense smoke is very suitable for this experiment, and by means of a lens the dust-free regions may be thus projected on to a screen. Diminished pressure makes the coat thicker. Increased pressure makes it thinner. In hydrogen it is thicker, and in carbonic acid thinner, than in air. We have also succeeded in observing it in liquids—for instance, in water holding fine rouge in suspension, the solid body being a metal steam tube. ”

“ To avoid an excess of oil, the following coats need turpentine to insure the same proportion of oil and pigment. As proof of this, prime a piece of wood and a piece of iron with the same paint; when the wood takes up part of the oil from the paint and leaves the rest in proportion to harden well, where at the same time the paint on iron remains soft. To be more lucid, it need be explained, linseed oil boiled has lost its oleic acid and glycerine ether, which form with the bases of pigments the insoluble soap, as well as its albumen, which in boiling is thrown out. It coagulates at 160° F. heat ”

“ It will be shown herewith that boiled oil, though in general use, is unfit for durable painting, that it is the cause of most of the troubles painters have to contend with, and that raw linseed oil seasoned by age is the only source to bind pigments for durable painting; but how to procure it is another trouble to overcome, as all our American raw linseed oil has been heated by the manufacturers, to qualify it for quick drying and an early market, thereby impairing its quality. ”

“ When a voltaic combination, in which the positive metal is thermo-negative, and the negative one is thermo-positive, is heated, the electric potential of the couple diminishes, notwithstanding that the internal resistance is decreased. ”