It is, however, probable that the one class runs into the other by imperceptible gradations.
For example, from the evidence of molar changes due to the obvious parts of bodies, science first comes to believe in molecular changes due to imperceptible particles, and then tries to conceive the ideas of particles, molecules, atoms, electrons.
These earthquake shocks have two distinct characteristics, a slight vibration, sometimes almost imperceptible, called a temblor, generally occurring at frequent intervals, and a violent horizontal or rotary vibration, or motion, also repeated at frequent intervals, called a terremoto, which is caused by a fracture or displacement of the earth's strata at some particular point, and often results in considerable damage.
It is lenticular in form, brightest near the sun, and shades off by imperceptible gradations, generally becoming invisible at a distance of 90° from the sun.
An absolutely imperceptible physiological difference arising as a variation may be of selective value, and it may carry with it correlated variations which appeal to the human eye but are of no selective value themselves.
Some of these, which may be called " earth-tremors," resemble earthquakes in the rapidity with which they occur, but differ from earthquakes in being imperceptible (owing to the smallness of the motion) until instrumental means are used to detect them.
But on the road, the highroad along which the troops marched, there was no such freshness even at night or when the road passed through the forest; the dew was imperceptible on the sandy dust churned up more than six inches deep.
Above the sea, are on the Pontotoc ridge in Tippah and Union counties; and from this ridge there is an almost imperceptible slope south and west from the Appalachian Mountain system.
Slope of the Blue Ridge is almost imperceptible, or confused with the numerous mountain slopes that rise above it.
They are comparatively inactive at all seasons; indeed, the action of the tides and back-waters and the tangle of vegetation in the sombre swamps and forests through which they run, often render their currents almost imperceptible at ordinary water.
It extends as a completely even plain of snow, with long, almost imperceptible, undulations or waves, at a height of 7000 to 10,000 ft., obliterating the features of the underlying land, the mountains and valleys of which are completely interred.
An extensive water-parting in the north central part of the state, an elevation whose inclination is almost imperceptible, determines the course of three great continental river systems. From this central elevation the land slopes off in all directions, rising again in the extreme north-east corner, where the rugged granite uplift in Cook county, known as the Misquah Hills, reaches an altitude of 2230 ft., the highest point in the state; and in the south-west corner, where an altitude of 1800 ft.
Some crystallizers are made entirely cylindrical, and are connected to the condenser of the vacuum pan; in order to maintain a partial vacuum in them, some are fitted with cold-water pipes to cool them and with steam pipes to heat them, and some are left open to the atmosphere at the top. But the efficiency of all depends on the process of almost imperceptible yet continuous evaporation and the methodical addition of syrup, and not on the idiosyncrasies of the experts who manage them; and there is no doubt that in large commercial processes of manufacture the simpler the apparatus used for obtaining a desired result, and the more easily it is understood, the better it will be for the manufacturer.
For there are many almost imperceptible stages of transition from the one to the other; and, for all the principal contentions of Ultramontanism, analogies may be found in the past history of the Catholic Church.
The moraines are of too small relief to be shown on any maps but those of the largest scale; yet small as they are, they are the chief relief of the prairie states, and, in association with the nearly imperceptible slopes of the till plains, they determine the course of many streams and rivers, which as a whole are consequent upon the surface form of the glacial deposits.
When, on the other hand, the objects of science are properly described as phenomena, what is meant is not this pittance of sensible appearances, but positive facts of all kinds, whether perceptible or imperceptible, whether capable of being experienced or of being inferred from, but beyond, experience, e.g.
At this stage collapse may set in, the patient become faint, the limbs twitch, the radical pulse become imperceptible, and unconsciousness supervene.
The titration is complete when the blue colour is so faint that it is almost imperceptible after the flask has been vigorously shaken.
Thus in many cases the difficulty of supposing that selection has acted on minute and imperceptible initial variations, so small as to have no selective value, may be got rid of.
But in both East and West, this theory of his became established only by very imperceptible degrees, and indeed, strictly speaking, the process was never completed.
The radio-activity of sea-water is extraordinarily small; indeed in samples taken from 50 fathoms in the Bay of Danzig it was imperceptible, and R.
3 In some cases a piece of land is only an island at high water, and by imperceptible gradation the form passes into a peninsula.