Slide rule

“ He gives no drawing of his “triangular quadrant,” hence his account of it is unsatisfactory. He explains the use of “gage-points.” His placing logarithmic lines on the edges of instrument boxes was outdone in oddity later by Everard who placed them on tobacco-boxes. [34] In Brown’s publication of 1704 the White slide rule is given again, “being as neat and ready a way as ever was used.” He tells also of a “glasier’s sliding rule.” William Leybourn explains in 1673 how Wingate’s double and triple lines for squaring and cubing, or square and cube root, can be used on slide rules. ”

“ Through Dr. Arthur Hutchinson of Pembroke College, Cambridge, I learned that Delamain’s writings on the slide rule were available. In this article will be given: First, some details of the changes introduced during the seventeenth century in the design of Gunter’s scale by Edmund Wingate, Milbourn, Thomas Brown, John Brown and William Leybourn; second, an account of Delamain’s book of 1630 on the slide rule which antedates Oughtred’s first publication (though Oughtred’s date of invention is earlier than the date of Delamain’s alleged invention) and of Delamain’s later designs of slide rules ”

“ To do this on the slide rule, put the index of the C scale opposite 8 on
the D scale and move the indicator to 9 on the C scale. Then move the
slider till the right-hand index of the C scale is under the hairline.
Now, move the indicator to 150 on the C scale and read the answer $108
on the D scale. Notice that in this, as in many practical problems,
there is no question about where the decimal point should go.
2. Sales Tax.
A man buys an article worth $12 and he must pay a sales tax of 1.5%. How
much does he pay? A tax of 1.5% means he must pay 1.015 * 12.00. ”

“ A pushed-back cap had the crossed slide-rule symbol of ship's computer man. ”

“ It consists (Fig. 2) of a rule, A, divided into equal or proportional parts, which pivots in the manner of a compass around a rod, T, that serves as a central rotary point. Along this rule moves a slide, R, provided with an aperture, C, which is made to coincide with one of the divisions. This division corresponds to the number of equal or proportional parts into which the circle is to be divided. The slide is provided with a wheel, E, that carries a point which serves at every revolution to trace the points that indicate the divisions of the circumference. ”

“ Whites rule” for the measuring of board and timber, round and square. He calls this a “sliding rule.” The existence, in 1661, of a “Whites rule” indicates activities in designing of which we know as yet very little. In his book of 1761, previously quoted, Brown gives a drawing of “White’s sliding rule” (p. 193) ; also a special contrivance of his own, as indicated by him in these words:
A further improvement of the Triangular Quadrant, as I have made it several times, with a sliding Cover on the in-side, when made hollow, to carry Ink, Pens, and Compasses ”

“ I just wish there was a slide near Calumet, so that I could take you down and let you see how splendid it is. Why, it's just like—let me see—I've got it! It's just like tobogganing on water. You jump on board the crib at the mouth of the slide, you know, and it moves along very slowly at first, until it gets to the edge of the first slant; then it takes a sudden start, and away it goes shooting down like greased lightning, making the water fly up all around you, just like the snow does when you're tobogganing. ”

“ The great slide is like common slides in that when once you have started you have to go on to the end—unless you fall down—and then it hurts just as much as the smaller kind on ponds. The great slide runs downhill all the way, so that you keep on going faster and faster and faster. George and Jane went so fast that they had not time to notice the scenery. ”

“ A slide is judged not by what it appears to be when held in the hand, but by its appearance when magnified two to five thousand times on the screen, where a small defect in the slide will show up as a gross fault. ”

“ An almost endless and likely profitless discussion has been indulged in as to the proper way to guide a slide rest, and different opinions exist. It is a question that, so far as principle is concerned, there ought to be some way to settle which should not only govern the question in regard to the slide rest of a lathe, but all slides that work against a torsional resistance, as it may be called—that is, a resistance that does not directly oppose the propelling power. ”

“ It is a good idea to procure a slide, as near technically perfect as possible, from some slide-making friend, or dealer, to use it as a standard, and to make slide after slide from the same negative until a satisfactory result is reached. ”

“ In the employment of Slide Turning Lathes, it is of great advantage to be able to reverse the motion of the Slide so as to enable the turning tool to cut towards the Head of the Lathe or away from it, and also to be able to arrest the motion of the Slide altogether, while all the other functions of the lathe are continued in action. ”

“ Paint it on your slide, and stop it out all round with asphaltum or any dense black. Then fix to it a simple spiral disk, such as that given in Fig. 2, and the instant the spiral spins the water will begin to flow.
In all designs remember that the fixed slide must be broken up with black and colour, so as not to show the whole of the spiral at once. The wave should, as it were, sweep over the windows. For front designs nothing is superior to a good knighthood star. ”

“ A Sliding-scale is a——well, it's a sort of patent mechanical contrivance for weighing out things, so as to make it fairer than ordinary scales do. (Plunges recklessly.) You can make it slide up or down, you know, and fix it at any point you like. ”

“ Even though the tool has little overhang it may tilt downward because the toolslide is loose on its ways, and for this reason the slide should have a snug adjustment that will permit an easy movement without unnecessary play. ”

“ He thrust his mittened hand through the snow to the earth to steady himself, and went on. But he was forced to exercise such care that the first zigzag consumed five minutes. Then, returning across the face of the slide toward the pine, he met with a new difficulty. The slide steepened considerably, so that little snow collected, while, bent flat beneath this thin covering, were long, dry last-year's grasses. ”

“ Copy the design through the glass, and it would be as well not to forget that unless you can draw properly on paper you are not likely to do so on a lantern slide, where in the intense light and enlargement every mistake and shakiness of line is exaggerated for the benefit of the spectators. For those who cannot draw, figures of men and animals can be cut out with scissors and pasted on the slide, so as to give a shadow entertainment, as a change from the bought slides. Others can buy transparencies and stick them on for themselves, but the result will never equal hand-painting. ”

“ The weather was stormy, and the mountain brook which ran along the slide concluded to waste no more labor in carving out a bed for itself in the rock, when it might as well be using the slide which it found ready made. And one fine day it broke into the slide and half filled it, so that the logs, when they were started down the steep incline, sent the water flying, turned somersaults, stood on end, and played no end of dangerous tricks which no one could foresee. ”

“ A clean slide must be selected, all through our pages we emphasise the cleanliness of slides, at or near its centre we put a drop of water and, lifting it with a brush, we place our section in the drop of water. If our examination is to be with a low magnification, we need not use a cover slip, nevertheless it is worth while to cultivate the habit of using one. ”

“ Again, the boys have their sleds; and sliding down hill is splendid fun. But they trip up some grave citizen, who sprains his shoulder. What is the result? Not the provision of a safe, good place, where boys may slide down hill without danger to any one, but an edict forbidding all sliding, under penalty of fine. ”

“ It is hard to maintain interest with single slides, but with a good series, or [Page 180] serial, you can actually make folks look forward to the next slide.
It is essential to secure the exclusive rights for your town. This is already possible, for the slide manufacturers have produced a number of excellent series in slides. This concession, which may be obtained by paying an additional fee, is important, because the slides can be filled in to suit almost any business. ”

“ On the appearance of the picture showing the group the fog incidental to a damp or new slide gradually appeared covering the whole slide, and only after some minutes cleared, and then quite contrary to usual practice did so from a central point just over the face that appeared in the centre, and refused even after that to clear right off to the edge. The general experience is for a slide to clear from the outside edges to a common centre. ”

“ Two of the cuts show the progress of the performance as seen by the audience. The third cut explains the mechanism. Behind the scenes is a strong frame, up and down which a movable slide works. Tackle is provided to raise and lower the slide; and a workman behind the scenes is intrusted with its manipulation. A bar carrying at its rear end handles, and in front a socket, shown in the upper right-hand corner of the same cut, is journaled in the slide, and can also be thrust in and out through the journal box. ”

“ All one had to do was to sink an axe into the dry trunk a dozen times, and it would fall to the ice and most probably smash conveniently to pieces. This Clay had figured on when confidently limiting the trip to half an hour.
He studied the cliff thoroughly before attempting it. So far as he was concerned, the longest way round was the shortest way to the tree. Twenty feet of nearly perpendicular climbing would bring him to where a slide sloped more gently in. By making a long zigzag across the face of this slide and back again, he would arrive at the pine. ”

“ Ambitious slide-makers generally aim at warm-toned slides for pictorial effect, and rightly. But slides intended for scientific purposes are generally better when cold in tone, the definition is usually better. ”

“ A long-legged man, sculling, may use a much longer slide than a short man. But in an eight, if the long man fits his stretcher as if for sculling, he will be doing more than his share, and may be unable to shoot so long a slide through in the required time, except by dint of ‘hurrying’ it; and, if he does this latter, the result is to cripple his swing, as shown supra. There must be a certain amount of give-and-take in arranging slides in an eight or four oar. That length of slide is best which all the crew can work simultaneously and effectively, preserving uniformity of swing and slide. ”

“ It was the spectacle, in earlier days of the slide, of this unorthodox sliding style beating good specimens of fixed-seat oarsmanship which so horrified many of the retired good oarsmen of the fixed-seat school. Before long the true use of the slide became better understood, and thus oarsmen—at all events scientific amateurs—began to realise that, while bad sliding could manage to command more pace than good fixed rowing, yet at the same time good sliding (which will be explained hereafter) will beat bad sliding by even more than the latter can distance good fixed-seat work. ”

“ PRACTISING STROKE (3) .
PRACTISING STROKE (4) .
[111] In 1871 Goldie’s (third) crew were supposed to do wonderful time (20 min. 11 sec.) , on a good spring and smooth day. It sufficed to make them hot favourites. In these days a sliding crew that could not beat 19 min. 40 sec. on a smooth spring tide would be reckoned to have a bad chance of success.
[112] The value of slides is therefore beyond dispute, but the oarsman should realise that good sliding distances bad sliding quite as far as bad sliding can beat fixed seats.
Hence the importance of using the slide to the best advantage. ”

“ D'ri had a plausible theory of the slide. He said that if we had clung to the sides of it to break our speed we 'd have gone down like a plummet and shattered our bones on a rocky shore. Coming fast, our bodies leaped far into the air and fell to deep water. ”

“ When the slide is well worn and slippery, these funny little beasts go down with great velocity, and seem to take as much pleasure in their frolicsome antics as if they were a crowd of boys and girls. ”

“ Referring to the third method, a compound slide rest provides an excellent method of turning tapers whose lengths are within the capacity of the upper slide of the compound rest, because that slide may be used to turn the taper, while the ordinary carriage feed may be used for the parallel parts of the work, and as the tailstock does not require to set over, the work centres are not subject to undue wear. ”

“ The advantage of the artificial slide is that it can be kept constantly in order, and therefore may be in first-class condition for sliding when the snow is altogether too soft and deep upon the hills. These slides are to be seen in every part of Canada, their gaunt framework rising up tall and stiff out of some level field, or, better still, upon a hill-top, thus securing a double elevation. ”

“ To realise what he has to do, let a man test separately his two forces which he has presently to combine. Let him row an ordinary fixed-seat stroke: this shows him the power of his swing; then let him sit upright, holding his oar, and, having slid up forward, kick back with rigid back and arms. He will feel that he grips the water even more forcibly for the instant by the second than by the former process. The fallacy of bad sliders is to be content with this gain of power in the action last named, and to substitute slide for swing (the arms eventually rowing the stroke home in either case) . ”