Intercrossing

“ In some cases the intercrossing of aboriginally distinct [Pg 48] species appears to have played an important part in the origin of our breeds. When several breeds have once been formed in any country, their occasional intercrossing, with the aid of selection, has, no doubt, largely aided in the formation of new sub-breeds; but the importance of crossing has been much exaggerated, both in regard to animals and to those plants which are propagated by seed. ”

“ Given sufficient variation, I believe divergent modification of a species in two lines could easily occur, even if free intercrossing occurred, because, the numbers varying being a large proportion of the whole, the numbers which bred like with like would he sufficient to carry on the two lines of divergence, those that intercrossed and produced less perfectly adapted offspring being eliminated. ”

“ For example, the phenomena of prepotency (whether as between varieties or between closely allied species) are found to occur when the two forms occupy a common area, i.e. are growing intermingled with one another. Therefore, but for this physiological differentiation, there could be absolutely nothing to prevent free intercrossing. ”

“ The interlocking system there affords the most perfect protection which can be devised against a most dangerous practice in railroad construction to which Americans are almost recklessly addicted. It is, also, matter of daily experience that the interlocking system does afford a perfect practical safeguard in this case. Every junction of a branch with a double track road involves a grade-crossing, and a grade-crossing of the most dangerous character. ”

“ We will notice that by employing a large impulse angle, and consequently a short radius, the intersection m of the two circles ii and cc is very safe, whereas, with the conditions reversed in favor of the impulse action, the intersection at k is more delicate. We have now seen enough to appreciate the fact that we favor one action at the expense of another. ”

“ When one link of the frame crosses another, the point of apparent intersection of the links is treated as if it were a real joint, and the stresses of each of the intersecting links are represented twice in the diagram of stress, as the opposite sides of the parallelogram which corresponds to the point of intersection. ”

“ And where, in rural areas, the traffic on the interregional highway is light or only moderately heavy, it may not be necessary, immediately at least, to go to the length of grade separation at all retained intersections But where a grade crossing permitted on the inter regional highway, the design of the intersection and its signing should enable and require operators of crossing vehicles to make a positive determination of the safety of crossing, and should reveal to operators of vehicles on the main highway the presence of vehicles about to cross or enter. ”

“ A well-made, carefully annealed steel-block reversible crossing is very smooth in the road, and has a long life. It is all in one solid piece; there are no parts to work loose or spread; the wear of the running surface is very uniform, and when the one side is much worn down, there is the other ready for service. The writer has had many of these steel-block [Pg 237] reversible crossings in use under heavy and fast traffic for six and eight years without turning.
Fig. 363 shows an ordinary crossing made of steel bull-head rails secured in strong cast-iron chairs ”

“ CROSSING.— The term `crossing ́ means a location within a State, other than a location where one or more railroad tracks cross one or more railroad tracks at grade where— (A) a public highway, road, or street, or a private roadway, including associated sidewalks and pathways, crosses one or more railroad tracks either at grade or grade-separated ”

“ It is so common to see a cross upon the roadsides, in various portions of this country, that I have endeavored to get some intelligible explanation of their design; but no one seems to have any more satisfactory solution than that these people think that they secure some immunity from all harm by the presence of a cross. They are seen very frequently at the forks of roads, at the point where a family path leads into the main road. ”

“ Since the crossing is always an effort, or, in economic terms, an expense, to be avoided as much as possible, the Road naturally avoids a double crossing, but, on the other hand, an island is a stronghold, and even a peninsula where two rivers meet is a potential stronghold. Therefore you have in the history of all early European roads a sort of dilemma, the first travellers debating, as it were, whether the occasion were sufficiently important to warrant the double crossing of the stream. ”

“ If something's not co-located or something's on top of each other, and one of the things that you've noticed in the approach is that flake intersection and the initial approach fix on the localizer are very close together. Those pop up and show up very graphically when you're looking at the charts and the creation of that. ”

“ The interlocking system is a very ingenious arrangement, by means of which the movements of a number of levers are interdependent, so that it is mechanically impossible for the signalman to move them except in their prearranged order. In approaching a switch there are two signals, the farther one indicating caution, and the home signal danger, if the switch is not locked in position so that the line is clear. The switch lever is the only one which can be moved, and its movement releases the lever of the caution signal. ”

“ A cross-way in the road or gateway is eagerly looked for as a retiring spot to the traveller, until the pursuing squadron, or heavily-loaded brigade, may have passed by.... As there are but few wheel-carriages to pass along them, the channel for the water and the path for the pack-horse are equally in the middle of the way, which is altogether occupied by an assemblage of such large and loose stones only as the force of the descending torrents have not been able to sweep away or remove. ”

“ The typical purpose of the law of interchange is, of course, to teach us how opposite natures may be helped and strengthened by receiving each, as far as they can, some impress or imparted power, from the other. ”

“ He rapidly constructed on the upper blank part of the paper, a proportional diagram consisting of two intersecting lines with a single cross-line.
"This long line," he explained, "is the distance from Stillbury's house to the Vauxhall railway bridge as it appears on the chart; the shorter cross-line is the same distance taken from the ordnance map. If our inference is correct and the chart is reasonably accurate, all the other distances will show a similar proportion. Let us try some of them. Take the distance from Vauxhall bridge to the Glasshouse Street bridge." ”

“ A hollow hub E is loosely journaled on the stem D, and is of sufficient length to extend over and have a bearing on the transmission shaft C, this latter being squared so it will turn with the hub, or it may be provided with a feather to work in a suitable groove in the hub, so that both will turn together, while permitting the hub to move longitudinally. ”

“ Right-turning access at grade-separated intersections.—Where, on rural sections of the system designed with four or more through-traffic lanes, access is to be provided from grade-separated intersecting roads, and the provision of direct connections for left- and right-turning movements is not feasible, ramps or connections between the intersecting highways shall be constructed in such manner as to permit exit from and entrance to the interregional highway by right-turning movements only. ”

“ If at any time two vessels, not end on, are seen, keeping the courses to be expected with regard to them, respectively, to be likely to arrive at the same point at or nearly at the same moment, they are vessels crossing, so as to involve risk of collision ”

“ In the chain every two adjacent links have a definite relative motion, that namely which belongs to the pair of elements connecting them. But two links which are connected by a third do not possess definite reciprocal motions except under certain conditions. Such motions can occur only if the chain be so arranged that every alteration in the position of a link relatively to the one next to it be accompanied by an alteration in the position of every other link relatively to the first. ”

“ If it has happened that through engineering difficulties-as the interposition of a mountain or a river-the line is deflected so as to cross the boundary, and run for the time being in another state than that of its principal location, does such detour in itself impress an external character on internal intercourse? ”

“ But in the case of our chain we must remember that although that 8-shaped link has two independent ends it is like every other link in having only two sides—that is, you cannot turn over one end without turning the other at the same time. ”

“ The distribution of the shearing stress over the cross-section is determined by the function ψ, already introduced. If we draw the curves ψ = const., corresponding to any form of section, for equidifferent values of the constant, the tangential traction at any point on the cross-section is directed along the tangent to that curve of the family which passes through the point, and the magnitude of it is inversely proportional to the distance between consecutive curves of the family. ”

“ If there are parallel ranges, it is correct to speak of a transverse axis, running at right angles with the main axis. There is, it is apparent, a marked difference between simple chains and the accumulated parallel chains, where breadth is a prominent element, as in the Vosges, the Black Forest Mountains, the Fichtel range, the Hartz, the Ardennes. The parallel rows form a mountain system. Yet all great chains are made up of smaller ones, of groups at least, and so are mountain systems. ”

“ Where vessels approaching are yet so distant from each other, or where the lines of approach, though parallel, are so far apart as not to involve risk of collision, that rule of navigation has no application to the case. ”

“ One constantly came upon those costly overhead cross-over places, where one set of lines is carried right over the top of another set at a junction, so that continuous traffic going one way shall not be checked by traffic coming in from the side and proceeding in the opposite direction—a plan seldom adopted at our most important railway centres. ”

“ Since the strike is the intersection of the bedding plane with a horizontal surface, and the dip is the intersection with that particular vertical plane which gives the steepest inclination, the strike and dip are perpendicular to each other. ”

“ The crossways creep and crawl like a winding thread, without beginning and without end. Sometimes their stretch tires and vexes— one wants to go by a shorter route and turns aside, goes astray, comes back to the former way. ”

“ One train of mechanism may diverge into two or more—as when a single shaft, driven by a prime mover, carries several pulleys, each of which drives a different machine. The principles of comparative motion in such converging and diverging trains are the same as in simple trains.
Division 6.—Aggregate Combinations.
§ 72. General Principles.—Willis designated as “aggregate combinations” those assemblages of pieces of mechanism in which the motion of one follower is the resultant of component motions impressed on it by more than one driver. ”

“ The fully developed cross of this sort consists of steps or calvary, socket, shaft or stem, capital or knop, and head. The latter, it should be remarked, is that part of the cross which, no doubt on account of the sacred or legendary significance of the figures sculptured upon it, is now most commonly absent. The remaining elements consisting of such simple units, it is truly wonderful how great variety of treatment is to be observed in crosses of the kind. The resources of their design may almost be said to be unlimited. ”

“ In the differential method, which is largely used on land lines, there is what is known as a differential relay, that is a relay wound with two sets of coils in each of which the current flows in a different direction. ”

“ Now, if you look at Diagrams 1, 2, and 3, you may be puzzled to declare whether there are in each case two or four new walls; but you cannot call them three, as required in our puzzle. The intersection either affects the question or it does not affect it.
If you tie two pieces of string firmly together, or splice them in a nautical manner, they become "one piece of string." If you simply let them lie across one another or overlap, they remain "two pieces of string." It is all a question of joining and welding. ”

“ The intersections of corresponding rays of a pencil of the second order in involution are all on a straight line u, and the intersection of any two tangents ab, when joined to the intersection of the corresponding tangents a'b', gives a line which passes through a fixed point U, the pole of the line u with respect to the conic. ”

“ We thus have the authority of this court that lands which are adjacent within the meaning of this act of 1875 must be lands in proximity, contiguous or near to, the line of the road. While 'proximity' or 'nearness' to an object is somewhat uncertain as a measure of distance, yet the use of such words as a definition brings to the mind the idea that lands which are in fact far off, or distant, are not adjacent. ”