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History Of The Arts And Sciences For 1797.
HISTORY OF THE ARTS AND SCIENCES FOR 1797 .
DESCRIPTION OF A NEW INVENTED LUNAR GLOBE . IfOHN RUSSELL , Esq . of Newman-street , has obtained letters J patent for a new apparatus , which he has called the Selenographia , or description of the Moon . This apparatus exhibits the lunar pIiEenomena more clear !* - than was done before . It consists of a globej on which are described the
ever spots on the moon ' s surface , beirig carefully engraved from the most accurate observations ; the lttnar mountains in particular being delineated with great exactness . The instrument to which the globe is-affixed g ives it those motions which are necessary to describe the effects produced to us upon the face of the moon , in its different degrees of elongation from the sun ,
under all states of libration , in , ongitude and latitude ; inclinati fi of the moon ' s equator to the plane of the ecliptic ; the first meridian of the moon with the plane of the illuminated hemisphere ; the apparent motion of the polar axis of the moon ; and the motion of the moon ' s mean centre , while performing her periodical circuit round the earth , and revolution on her own axis , during the cycle . On this globe the lunar mountains may be elevated according . to their proportionate magnitudes ; but for . the globe , which has not these elevations , a spherical segment is contrived , upon which are elevated
the various mountains seen on the surface of the moon ; and it may be coloured so that those spots maybe properly represented , which owe their respective dark or lig ht appearances not to elevation , but to other causes . The instrument to move this g lobe is composed principally of circles , semicircles , and segments of spheres and of circles , so
placed ,, that the radius of each will unite in a common centre , which is that of theiunar giobe itself . Besides the striking utility of an accurate delineation of the moon for astronomical purposes , it cannot but be an Object of great curiosity . Hevelius , so far back as 16 47 , expressed his wish to see such an instrument as this completed ; but it was not till 1 745 that any
thing like it was carried into effect , when Tobias Mayer undertook it , and made considerable progress in the design , but left it uncompleted at his death . Upon the lunar globe are marked , in faint lines , three great circles ; the one horizontal , the rest vertical . The first represents the equatorwhich is laced upon that spot named Censorinusand runs
, p , within three degrees north latitude ot'Grimaldus . The second is the prime meridian , which , passing through the poles , intersects the equator at a right angle , in that point which is the mean centre of the moon ' s libration . The third represents the boundary of vision VOL . ix . e
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
History Of The Arts And Sciences For 1797.
HISTORY OF THE ARTS AND SCIENCES FOR 1797 .
DESCRIPTION OF A NEW INVENTED LUNAR GLOBE . IfOHN RUSSELL , Esq . of Newman-street , has obtained letters J patent for a new apparatus , which he has called the Selenographia , or description of the Moon . This apparatus exhibits the lunar pIiEenomena more clear !* - than was done before . It consists of a globej on which are described the
ever spots on the moon ' s surface , beirig carefully engraved from the most accurate observations ; the lttnar mountains in particular being delineated with great exactness . The instrument to which the globe is-affixed g ives it those motions which are necessary to describe the effects produced to us upon the face of the moon , in its different degrees of elongation from the sun ,
under all states of libration , in , ongitude and latitude ; inclinati fi of the moon ' s equator to the plane of the ecliptic ; the first meridian of the moon with the plane of the illuminated hemisphere ; the apparent motion of the polar axis of the moon ; and the motion of the moon ' s mean centre , while performing her periodical circuit round the earth , and revolution on her own axis , during the cycle . On this globe the lunar mountains may be elevated according . to their proportionate magnitudes ; but for . the globe , which has not these elevations , a spherical segment is contrived , upon which are elevated
the various mountains seen on the surface of the moon ; and it may be coloured so that those spots maybe properly represented , which owe their respective dark or lig ht appearances not to elevation , but to other causes . The instrument to move this g lobe is composed principally of circles , semicircles , and segments of spheres and of circles , so
placed ,, that the radius of each will unite in a common centre , which is that of theiunar giobe itself . Besides the striking utility of an accurate delineation of the moon for astronomical purposes , it cannot but be an Object of great curiosity . Hevelius , so far back as 16 47 , expressed his wish to see such an instrument as this completed ; but it was not till 1 745 that any
thing like it was carried into effect , when Tobias Mayer undertook it , and made considerable progress in the design , but left it uncompleted at his death . Upon the lunar globe are marked , in faint lines , three great circles ; the one horizontal , the rest vertical . The first represents the equatorwhich is laced upon that spot named Censorinusand runs
, p , within three degrees north latitude ot'Grimaldus . The second is the prime meridian , which , passing through the poles , intersects the equator at a right angle , in that point which is the mean centre of the moon ' s libration . The third represents the boundary of vision VOL . ix . e