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New regulator for temperatures
336
Mechanics, Physics, and Chemistry.
before it was silvered that a flaw had occurred daring the process of cooling. On its arrival at M, Sautter's workshops, it was reduced in dimensions by bringing it nearer to the required shape, and by cutting a groove to fix the mechanism necessary for its manipulation. It then passed into the hands of M. Secr(~tan's skilful operatives, who ground it with a counter piece of glass, 50 centimetres in diameter, assisted by emery and water. This process, which was frequently tested by the spherometer, occupied a week, at the end of which time a fine grained and exactly spberic~d surface was obtained. Having been thus prepared, it.was polished by hand, the polisher employed being 22 centimetres in diameter, and covered with rouge. This polishing was completed by one able workman in another week, and the Inirror was changed from the spherical to the paraboloid form. From this moment its success ~[ppeared certain, and it was removed, with tile necessary tools, to the Observatory, to be optically tested~ and to receive the finishing touches. The frame and strand were made by M. Eichens, the director of )5. Secrdtan's works. The telescope is suspended from its centre of gravity by two trunnlons, resting on two solid vertical columns. It possesses vertical and azimuthic~d movements, so that it only requires to have its inclination adjusted to the latitude of the place in whic~ it may finally rest, to constitute a veritable equatorial. In consequence of the complaints made b)" the French astronomers of the unfavorable atmosphere of Paris, the new telescope will be placed in an observatory to be erected in the south, and specially devoted to original investigations. On the 28th ult., M. Le Yerrler exhibited to the Academy a drawing representing the double nebula iu Canes Venatici--the wonderful spiral formation of which was made known through the magnificent instrument at Parsonstown~as seen by the Foucault mirror. The Abb~ ]~loigno tells us that the drawing exhibits "incomparably more details than those givon by tierschel and Lord Rosse." If this be correct, the Foucault telegraph must possess an enormous advantage over the oht form of reflectors, as the diameter of the new instrument is less than half that at Parsonstown. We understand that four-inch instruments of this description, in a square mahogany frame, elevated or depressed by a rack movement like that of a re~ding desk, may be had in Paris for £10. They are, however, liable to become tarnished~ when they need an inexpensive process of repair.
New Regulatorfor Temperatures. A committee of the French Academy of Sciences reports very favorably of a new automatic temperature-regulator which M. Eugene Rollaud has attached to his Mechanical Roaster, and which~ the committee say, has worked for eight years with the precision of a piece of physical apparatus and the certainty of a practical machine. The combustion of the furnace is regulated by balance valves on the
On the Strength of ~'on and Timber Pillars.
337
pipes through which the air is'introduced, which valves are automatically governed by the regulator. This regulator consists of a mercury gauge, the closed branch of which is attached to a fixed support, while the cistern is freely suspended to the beam of a balance ; the varying Weight in this branch will cause the beam to assume different positions depending on the temperature of the apparatus, which variation of position may be used to govern the valve. In order to prevent the barometric changes from affecting the appa'ratus, the closed end of a syphon barometer whose tube is of the same diameter with the gauge, is attached to the be~m, while its cistern is sustained by the fixed support. The barometric changes will then a~'eet these two instruments equally and in opposite directions, and will consequently have no effect on the position of the balance beam.--G)n~ytes lgendus of the Acade~y of b'cienees, July~ 1862. l%r the Jounlal
of the Franklin
Iustituie.
Strength of Cast [ron and Timber -Pillars : A series of Tables showing the Breaking Weight of Cast Iron, Dantzic Oak, and Red Deal :Pillars. By W~. B~Yso~, Cir. Eng. ( C o n t i q u e d f r o m p a g e 1_'23.)
Solid Uniform Square Pillars of Da~lzie Oak, Both Ends being Flat and Firmlq l, Txe,'l, ¢9
r Calculated breaking weight i n toll8 fPOlil forlxPula
Value of w in tons tl'Olll rot'ill lll~t D4 V,' ~ 10"95 ~2
w~
f Y
10~ 9 l0 lI
13} 14~ 16 20
28
29k 33k 84~a6 as~40 VoL. X L I V . - - T m a D
1122"54 886'95 718 42 593"74 498'90 425"10 366"54 319'30 280-63 248'59 221'73 199"0l 179.60 162'90 148'43 135'S0 124'72 114'94 106'27 98"55 9P63 85'42 79'82
279"53
4~
~zaiss.--,No. 5.--~'ov~.~ug~, 1862.
Wc
~g
w + ~"
235"54 226"09 21638 .206'58 . 196'82 187"20 177 82 168'74 169'00 151.64 143.6~ 136'12 128 97 122'22 115'87 109-88 104"26 98'98 94 '03 89'38 8501 80'92 77'08
2"90 2'79 2.67 2'55 2'43 2'31 2"19 2'08 1 '97 1"87 177 1'68
1'59 1 '50 1"43 1'35 1"28
1"22 1"16 l'lO 1'04
0"99 0'95 29
Mechanics, Physics, and Chemistry.
before it was silvered that a flaw had occurred daring the process of cooling. On its arrival at M, Sautter's workshops, it was reduced in dimensions by bringing it nearer to the required shape, and by cutting a groove to fix the mechanism necessary for its manipulation. It then passed into the hands of M. Secr(~tan's skilful operatives, who ground it with a counter piece of glass, 50 centimetres in diameter, assisted by emery and water. This process, which was frequently tested by the spherometer, occupied a week, at the end of which time a fine grained and exactly spberic~d surface was obtained. Having been thus prepared, it.was polished by hand, the polisher employed being 22 centimetres in diameter, and covered with rouge. This polishing was completed by one able workman in another week, and the Inirror was changed from the spherical to the paraboloid form. From this moment its success ~[ppeared certain, and it was removed, with tile necessary tools, to the Observatory, to be optically tested~ and to receive the finishing touches. The frame and strand were made by M. Eichens, the director of )5. Secrdtan's works. The telescope is suspended from its centre of gravity by two trunnlons, resting on two solid vertical columns. It possesses vertical and azimuthic~d movements, so that it only requires to have its inclination adjusted to the latitude of the place in whic~ it may finally rest, to constitute a veritable equatorial. In consequence of the complaints made b)" the French astronomers of the unfavorable atmosphere of Paris, the new telescope will be placed in an observatory to be erected in the south, and specially devoted to original investigations. On the 28th ult., M. Le Yerrler exhibited to the Academy a drawing representing the double nebula iu Canes Venatici--the wonderful spiral formation of which was made known through the magnificent instrument at Parsonstown~as seen by the Foucault mirror. The Abb~ ]~loigno tells us that the drawing exhibits "incomparably more details than those givon by tierschel and Lord Rosse." If this be correct, the Foucault telegraph must possess an enormous advantage over the oht form of reflectors, as the diameter of the new instrument is less than half that at Parsonstown. We understand that four-inch instruments of this description, in a square mahogany frame, elevated or depressed by a rack movement like that of a re~ding desk, may be had in Paris for £10. They are, however, liable to become tarnished~ when they need an inexpensive process of repair.
New Regulatorfor Temperatures. A committee of the French Academy of Sciences reports very favorably of a new automatic temperature-regulator which M. Eugene Rollaud has attached to his Mechanical Roaster, and which~ the committee say, has worked for eight years with the precision of a piece of physical apparatus and the certainty of a practical machine. The combustion of the furnace is regulated by balance valves on the
On the Strength of ~'on and Timber Pillars.
337
pipes through which the air is'introduced, which valves are automatically governed by the regulator. This regulator consists of a mercury gauge, the closed branch of which is attached to a fixed support, while the cistern is freely suspended to the beam of a balance ; the varying Weight in this branch will cause the beam to assume different positions depending on the temperature of the apparatus, which variation of position may be used to govern the valve. In order to prevent the barometric changes from affecting the appa'ratus, the closed end of a syphon barometer whose tube is of the same diameter with the gauge, is attached to the be~m, while its cistern is sustained by the fixed support. The barometric changes will then a~'eet these two instruments equally and in opposite directions, and will consequently have no effect on the position of the balance beam.--G)n~ytes lgendus of the Acade~y of b'cienees, July~ 1862. l%r the Jounlal
of the Franklin
Iustituie.
Strength of Cast [ron and Timber -Pillars : A series of Tables showing the Breaking Weight of Cast Iron, Dantzic Oak, and Red Deal :Pillars. By W~. B~Yso~, Cir. Eng. ( C o n t i q u e d f r o m p a g e 1_'23.)
Solid Uniform Square Pillars of Da~lzie Oak, Both Ends being Flat and Firmlq l, Txe,'l, ¢9
r Calculated breaking weight i n toll8 fPOlil forlxPula
Value of w in tons tl'Olll rot'ill lll~t D4 V,' ~ 10"95 ~2
w~
f Y
10~ 9 l0 lI
13} 14~ 16 20
28
29k 33k 84~a6 as~40 VoL. X L I V . - - T m a D
1122"54 886'95 718 42 593"74 498'90 425"10 366"54 319'30 280-63 248'59 221'73 199"0l 179.60 162'90 148'43 135'S0 124'72 114'94 106'27 98"55 9P63 85'42 79'82
279"53
4~
~zaiss.--,No. 5.--~'ov~.~ug~, 1862.
Wc
~g
w + ~"
235"54 226"09 21638 .206'58 . 196'82 187"20 177 82 168'74 169'00 151.64 143.6~ 136'12 128 97 122'22 115'87 109-88 104"26 98'98 94 '03 89'38 8501 80'92 77'08
2"90 2'79 2.67 2'55 2'43 2'31 2"19 2'08 1 '97 1"87 177 1'68
1'59 1 '50 1"43 1'35 1"28
1"22 1"16 l'lO 1'04
0"99 0'95 29