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Seite 541 - Naturalists continually refer to external conditions, such as climate, food, &c., as the only possible cause of variation. In one limited sense, as we shall hereafter see, this may be true; but it is preposterous to attribute to mere external conditions, the structure, for instance, of the woodpecker, with its feet, tail, beak, and tongue, so admirably adapted to catch insects under the bark of trees.
Seite 513 - This substance may be allowed to flow away, or, if the metal is contained in a suitable porous receptacle, the fusible oxide sinks into this containing vessel ; in either case the oxidation of the lead affords a means of separating it from precious or inoxidisable metals if any were originally present in the lead. The above fact has been known from remote antiquity, and the early Jewish writers allude to it as old and well known.
Seite 128 - Sir Richard Phillips had four valuable qualities; honesty, zeal, ability, and courage. He applied them all to teaching matters about which he knew nothing; and gained himself an uncomfortable life and a ridiculous memory.
Seite 127 - NY, who, after having adopted a vegetable diet for sixteen months, thus writes : " I do not go beyond the truth when I say that I cannot find a man to vie with me in the field, •with the scythe, the fork, or the axe. I do not want anything but potatoes and salt, and I can cut and put up four cords of wood in a day, with no very great exertion.
Seite 513 - Arabian, gives, if mediaeval translations of his works are to be trusted,4 a sufficiently accurate description of the process to enable it to be conducted at the present day with no other aid than his ; but it must be remembered that it was the object of the alchemist to distinguish silver from gold, and to isolate the metals, rather than to determine the amount of one metal present in admixture with another. Geber calls the process of cupellation the trial of the cineritium, and he points out, in...
Seite 513 - ... lump, make a round and smooth hollowness, and upon the bottom of it strew a small quantity of glass beaten to powder, which lay to dry. When dry put your metal into the hollowness thereof, which you would try to prove, put coals of fire upon it, then blow with bellows upon the surface till the metal flows : upon which, being in flux, cast part after part of lead, and blow with a flame of strong ignition ;" this is to be continued " until the lead is vanished...
Seite 94 - Fickeissen and Becker, of Villingen, Baden. The plates or surfaces can be prepared from paper, cloth, or other suitable fabric or material, but by preference from white paper containing very little size and not much grain. This paper is first extended on a frame, or other arrangement, according to the size of the plate or surface which is desired. After it is dry, the surface is covered with a fine coat of copal...
Seite 127 - Ibs., by a young man, whose health had been indifferent at the beginning of the experiment. Only two prisoners lost at all in weight, and the quantity in each case was trifling. The prisoners all expressed themselves quite satisfied with this diet, and regretted the change back again to the ordinary diet.
Seite 513 - ... part of the mass, as a larger proportion of gold would protect the alloy from the solvent action of the acid, and the greater the amount of gold the less perfect would be the attack of the acid. In any case the first stage of assaying a gold alloy, say a sovereign, is to melt it with such an amount of silver as shall yield a button containing rather less than one-third of its weight of gold.
Seite 177 - Megalotrocha alhoflavicans, or Lacinularia socialis, would send living specimens to Dr. CT Hudson, who was much in want of them for his forthcoming work on the Rotatoria. The President announced that the following resolution had that evening been passed by the Council, and gave notice that a special meeting of the Society would be held on the 14th May next, for the purpose of taking it into consideration, and passing such resolutions as might be considered desirable, whether by alteration of the...