The optical manual, or, handbook of instructions for the guidance of surgeons in testing the range and quality of vision of recruits and others seeking employment in the military services of Great Britain, and in distinguishing and dealing with optical defects among the officers and men already engaged in them / by T. Longmore.

  • Longmore, T. (Thomas), Sir, 1816-1895.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: The optical manual, or, handbook of instructions for the guidance of surgeons in testing the range and quality of vision of recruits and others seeking employment in the military services of Great Britain, and in distinguishing and dealing with optical defects among the officers and men already engaged in them / by T. Longmore. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    targets and employed in educating men in the xise of the rifle at the various range practices have not been designed, as shown in the text, on an uniform visual standard, but seem rather to have been settled, especially as regards their dimensions at the various distances at which they are usually placed for firing practice, according to the proportions which have been considered, from personal observation, to be the most suitable for marks to be aimed at. There is apparently no sufficient reason why all such objects should not be fashioned on a regularly graduated scale of dimen- sions and config-uration in relation to distance, and be in exact accordance with the optical conditions, so far as the objects them- selves are concerned, under which they would present themselves as marks to be tired at in actual warfare. If a series of objects on such principles should be brought into use, the quality of sight necessary for a satisfactory execution of the contemplated task at any particular range of practice could be defined with almost mathematical precision. Medical officers at present only have to determine the question whether a man is optically fit for military service so far as the possession of a set minimum standard of vision is concerned ; but in performing the duties of recruiting, they may have in the future to answer several questions of a more complex kind. They may be required to furnish information on such questions as the follow- ing : Is the man visually qualified to become a marksman up to the longest range for which the rifle is capable of adjustment ] If not fit for a complete marksman, up to which class of practice does his visual power admit of the man being advantageously trained ? If not fit for the use of an arm of precision in the first line of the army, is he fit for duty in the ranks of the Militia or Volunteer forces ? If not fit for the duties of a rifleman, is he visually qualified for service in the Commissariat and Transport, or for any other corps or department of the ai my ? After a sufficient number of records on these subjects have been accumulated, a con- clusion may be arrived at on certain questions, which are regarded under different aspects in diff'erent armies, and which may well admit of diff'erent solutions in different countries ; as, for example, whether the proportion of men in this country, whose sharpness of sight is inferior to the normal standard owing to refractive defects, is so great as to render it advisable, from a military and financial point of view, to allow correcting spectacles to be used in the ranks