River gardens; an account of the best methods of cultivating fresh-water plants in aquaria


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Página 42 - ... elasticity belonging to them, and which leads to the effort on their part, whenever, as on being placed for observation on the field of the microscope, must be the case, they are bent or put out of a straight line, to recover that position which is natural to them. This elastic property of the filaments, currents almost imperceptible in the liquid in which they are immersed, and perhaps unequal attractions amongst the filaments themselves, are causes amply sufficient to explain any motion which...
Página 7 - ... became again excited, and I determined to watch and see if any other change would follow. Taking a book, therefore, I sat down near the object of my attention. I had not read many pages, turning frequently towards the remains upon the stick, when suddenly — I shall never forget the surprise of the moment — when suddenly the opening of the back was much widened, as by some sudden effort, and the greater part of a glittering Dragon-fly became plainly visible ; very quickly the whole insect...
Página 90 - ... because the streaky markings are not altogether unlike Chinese characters. It is of a pure white sparingly dashed with patches of pearly pink on the body, and having some exquisite letter-like markings or tracings about the head and tail. Another variety of the species is rich scarlet, shading off to black on the back, in the midst of which is a large cross of pure white having two transverse bands like the Cross of Lorraine, by which name the author thinks proper to designate it. PART II. THE...
Página 43 - College, Birmingham. The Oscillatorise belong to a group of plants which seem to stand immediately between the animal and vegetable kingdoms. After very careful and repeated examinations, the author has fully satisfied himself that the motions of this family of freshwater Algae are entirely independent of any electrical influence; of any current in the fluid in which they are placed ; or of any effort to recover their straight position. The motions, in fact, have very much the appearance of being...
Página 43 - Oscillatoriffi, if carefully watched, may be seen to move in various directions, sometimes to the right, sometimes to the left ; sometimes slowly, sometimes briskly. The author, however, never perceived in them anything like an effort to recover the straight position which is considered to be natural to them. On the contrary, they may often be observed to bend gradually, so as to form a very considerable curve ; to return again to the straight position, and then...

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