Comentarios de la gente - Escribir un comentario
No encontramos ningún comentario en los lugares habituales.
Otras ediciones - Ver todas
acid action angle animal aperture appear balsam become blood blood-corpuscles body cause cells central changes coloured coloured blood-corpuscles considerable containing continued contour contraction corpuscles course cover crystals described diameter diatoms difficult direction distinct double edge entirely examination existence experiments extremely fact field figures fluid give given glass granules greater illumination immersion inch indices interesting Journal layer length lens less light limit matter means measured meeting membraneous method microscope minute nature nucleus object observed obtained ordinary organs plate portion position possible preparation present President produced Professor protoplasm question rays referred refraction regard remains rendered represented round seen separated side similar slide Society solution species specimens stage staining structure substance surface taken thickness thin true tube whole
Página 227 - Report on the Hydroida collected during the Exploration of the Gulf Stream by LF de Pourtales, Assistant United States Coast Survey.
Página 123 - ... unfetters the mind from prejudices of every kind, and leaves it open and free to every impression of a higher nature which it is susceptible of receiving, guarding only against enthusiasm and self-deception by a habit of strict investigation, but encouraging, rather than suppressing, everything that can offer a prospect or a hope beyond the present obscure and unsatisfactory state.
Página 157 - The following list of presents was read, and the thanks of the meeting were voted to the respective donors ; viz., FOR THE LIBRARY.
Página 53 - numerical aperture " is equal to the product of the refractive index of the medium in front of the objective, multiplied into the sine of the semi-angular aperture=n sin. w. This definition of "numerical aperture" offers at once a means by which all objectives, whether dry, water, or oil .immersion, can be directly compared. It is based on the theory whence Professors Abbe and Helmholtz deduced the limit of visibility. The...
Página 158 - The President proposed a vote of thanks to the author of the paper, and also to Mr.
Página 31 - President, in the chair. The minutes of the preceding meeting were read and confirmed.
Página 121 - In mathematics, chemistry, and every branch of natural philosophy, how many are the inquiries necessary for their improvement and completion, which, taken separately, do not appear to lead to any specifically advantageous purpose ! Ho'w many useful inventions, and how much valuable and improving knowledge, would have been lost, if a rational curiosity, and a mere love of information, had not generally been allowed to be a sufficient motive for the search after truth !" — Malthus's Principles of...
Página 91 - Society during the past month was read by the Secretary, and the thanks of the meeting were voted to the donors.
Página 180 - ... is as a rule prevented. I may add that Mr. Gosse has already dealt with the action of the manubria in other rotifers (I. c.). Now I do not know how it may strike others, but to me this mechanism is simply exquisite. We have three distinct lines of power, all at work and in rotation. In the first place there is a power at hinge K, then follows the power at hinge H, and then lastly comes that of the manubria ; the moment the main upper handles of the ramus get together, then, and not before, up...