ما يقوله الناس - كتابة مراجعة
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الصفحة 7 - And here at the end of this chapter I will set before your eyes a type of a ' squirt' which hath been devised to cast much water upon a burning house, wishing a like squirt and plenty of water to be alwaies in a readinesse where fire may do harme ; for this kind of squirt may be made to holde an hoggeshed of water, or if you will, a greater quantity thereof, and may be so placed on his frame, that with ease and a smal strength, it sahl be mounted, imbased or turned to any one side, right against...
الصفحة 346 - The copy of a painting or the profile, immediately after being taken, must be kept in an obscure place ; it may, indeed, be examined in the shade> but in this case the exposure should be only for a few minutes ; by the Light of candles or lamps, as commonly employed, it is not sensibly affected.
الصفحة 244 - Nor when cold Winter keens the brightening flood, Would I weak-shivering linger on the brink.
الصفحة 84 - As the three angles of a plane triangle are equal to two right angles, that is, to 180° (Euc, 32. 1.) the' sum of any two of them is the supplement of the other.
الصفحة 414 - We shall find (especially if the paper has been kept some weeks before the trial is made) that its sensibility is greatly diminished, and, in some cases, seems quite extinct. But if it is again washed with a liberal quantity of the solution of silver, it becomes again sensible to light, and even more so than it was at first. In this way, by alternately washing the paper with salt and silver, and drying it between times, I have succeeded in increasing its sensibility to the degree that is requisite...
الصفحة 345 - In the spring of 1834, I began to put in practice a method which I had devised some time previously, for employing, to purposes of utility, the very curious property which has been long known to chemists to be possessed by the nitrate of silver, namely, its discolouration when exposed to the violet rays of light.
الصفحة 414 - This paper, if properly made, is very useful for all ordinary photogenic purposes. For example, nothing can be more perfect than the images it gives of leaves and flowers, especially with a summer sun : the light passing through the leaves delineates every ramification of their nerves.
الصفحة 150 - Prussian Blue that has undergone this process of digestion, as described, requires but a small quantity of Oxalic acid to dissolve it. About one part of Oxalic acid will dissolve six parts of Prussian Blue, (the weight taken before digesting in the acid.) This will answer for a concentrated solution, but for a dilute solution, more acid will be required.
الصفحة 376 - Is made by grinding upon a porphyry slab, with a muller, gold leaves along with white honey, till they be reduced to the finest possible division. The paste is then collected upon the edge of a knife or spatula, put into a large glass, and diffused through water. The gold, by gravity, soon falls to the bottom, while the honey dissolves in the water, which must be decanted off. The sediment is to be repeatedly washed till entirely freed from the honey. The powder, when dried, is very brilliant ; and,...