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Experimental proof of the quantizing of direction in the magnetic field. The Magnetic Moment of the Silver Atom
July. ry4.1
U. S. BUREAU OF MINES
NOTES.
‘13
products under different retorting conditions. The rates used were I c.c., 0.5 c.c., 0.33 c.c., 0.25 CC, and 0.2 C.C. per minute. All After all the oil had distilled, other conditions were kept constant. heating of the shale was continued for thirty minutes at the same This method gave gas yields which are standard temperature. comparable, but they do not represent the maximum yields obtainable. Enough runs were made at the rates of I and 0.2 cc. per minute to obtain enough oil (300 c.c.) for the regular distillation. In the tests at the intermediate rates only enough oil (60 cc.) was produced for a distillation in a modified 100 C.C. Engler flask, which has the side-arm one inch higher than the standard flask. The oil was distilled through a fractionating column, 4% inches long, of iron “ jack ” chain, and the distillate collected at the rate of one drop per second. Serial 2603, containing detailed tables of the results of the distillation tests, has been recently issued by the Bureau. All of the shales examined yielded more oil at the fast rate, that is, I C.C. per minute, than at the slow rate, 0.2 C.C. per minute, but at the slower rates the quality of the oils was superior to that of the oils produced at the faster rates. The Colorado shales, all of which are from the Green River formation, have more resemblance to each other than to the shales from the other regions, yet there is enough variation in the nature The of the products to distinguish each shale from the others. Australian and Scottish shale oils showed the highest saturation of any of the oils tested. This seems to indicate the superiority of the oils produced from the foreign shales. The oils from the Scottish, Nevada and Australian shales were similar to the crude petroleums of the so-called “ paraffin base ” ; the Kentucky shale oil was rich in asphalt, and the Colorado and Utah shale oils tested were intermediate. Experimental Proof of the Quantizing of Direction in the Magnetic Field. The Magnetic Moment of the Silver Atom. W. GERLACH and 0. STERX. (Zeit. f. Plzysib, Vol. 9, Ig22.)In an electrically heated vessel silver was evaporated. A beam of the gaseous atoms of metal escaped through a hole I sq. mm, in area. After moving for 2.5 cm. it fell on a screen with an aperture of .oo3 sq. mm. The portion of the original beam that came through this travelled 3.3 cm. and) then met a screen with a slit in it, .8 mm. long and .03 or .04 mm. wide. A vacuum of about .OOOOI mm. of mercury was maintained in the entire space included in the apparatus.
114
CURRENT
TOPICS.
[J. F. I.
The slit is just at the beginning of the sharp edge of a wedgeshaped electromagnet. The tiny beam of silver atoms, after passing through the slit, moves parallel to this edge, which is 3.5 cm. long, at less than .5 mm. from it. At the further end of the edge the ray The process strikes upon a glass plate on which it forms a deposit. was continued for eight hours and even after this length of time the quantity of silver deposited was so small that a method of developWhen the magnetic ment needed to be used to bring it into evidence. field was absent, there was revealed a strip of deposit 1.1 mm. long with a width varying from .06 to .I mm. With the magnetic field In the middle of present the shape of the deposit is very different. the area there is a portion of the glass showing no deposit at all. This has the form of a section of a double convex lens taken parallel to the axis. In the direction away from the magnetic edge there is a deposit bordering the unaffected middle space and there is a similar deposit on the side toward the edge. Right opposite the edge appears “ The impressions a projection of deposit like the boss of a shield. show that the ray of silver atoms in a non-homogeneous magnetic field is divided into two parts, one of which is attracted to the edge There was of the magnetic pole while the other is repelled from it.” no trace of atoms that were neither attracted nor repelled. The attraction was stronger than the repulsion. In commenting on this highly important experiment, J. C. McLennan, in his presidential address before the Section of Mathematics and Physics of the B.A.A.S. last September, said: “ From these results it was concluded that all the silver atoms in the stream of vapor possessed a definite magnetic moment, and that while the atoms were passing through the magnetic field their magnetic axes had two distinct orientations in space.” In further interpretation of the phenomena observed this additional citation is worth while : “ One of the most surprising and interesting developments of the quantum theory is that which shows that quantum numbers determine not only the size and form of the electron is Keplerian orbits in atoms, but also the orientation of these orbits in space with regard to a favored direction such as that provided by an interatomic or by an external magnetic or electric field of force. For any arbitrary value of the azimuthal quantum number k, the simple theory shows that there are exactly (k + I ) quantum positions of the orbital plane characterized by whole numbers. For example, if k = I the normal to the orbit may be either parallel to the direction of the controlling field or at right For silver k does angles to it.” (Should this not be at 1%” to it?) equal I. Hence the atoms of this metal set themselves in one of the two possible positions and accordingly form parts of one or other of the two rays into which the original ray is divided. The two authors made a subsequent study of the rate of variation of the magnetic field and came to the interesting additional conclusion that “the magnetic moment of the normal silver atom in the gaseous state is one Bohr magneton.” G. F. S.
U. S. BUREAU OF MINES
NOTES.
‘13
products under different retorting conditions. The rates used were I c.c., 0.5 c.c., 0.33 c.c., 0.25 CC, and 0.2 C.C. per minute. All After all the oil had distilled, other conditions were kept constant. heating of the shale was continued for thirty minutes at the same This method gave gas yields which are standard temperature. comparable, but they do not represent the maximum yields obtainable. Enough runs were made at the rates of I and 0.2 cc. per minute to obtain enough oil (300 c.c.) for the regular distillation. In the tests at the intermediate rates only enough oil (60 cc.) was produced for a distillation in a modified 100 C.C. Engler flask, which has the side-arm one inch higher than the standard flask. The oil was distilled through a fractionating column, 4% inches long, of iron “ jack ” chain, and the distillate collected at the rate of one drop per second. Serial 2603, containing detailed tables of the results of the distillation tests, has been recently issued by the Bureau. All of the shales examined yielded more oil at the fast rate, that is, I C.C. per minute, than at the slow rate, 0.2 C.C. per minute, but at the slower rates the quality of the oils was superior to that of the oils produced at the faster rates. The Colorado shales, all of which are from the Green River formation, have more resemblance to each other than to the shales from the other regions, yet there is enough variation in the nature The of the products to distinguish each shale from the others. Australian and Scottish shale oils showed the highest saturation of any of the oils tested. This seems to indicate the superiority of the oils produced from the foreign shales. The oils from the Scottish, Nevada and Australian shales were similar to the crude petroleums of the so-called “ paraffin base ” ; the Kentucky shale oil was rich in asphalt, and the Colorado and Utah shale oils tested were intermediate. Experimental Proof of the Quantizing of Direction in the Magnetic Field. The Magnetic Moment of the Silver Atom. W. GERLACH and 0. STERX. (Zeit. f. Plzysib, Vol. 9, Ig22.)In an electrically heated vessel silver was evaporated. A beam of the gaseous atoms of metal escaped through a hole I sq. mm, in area. After moving for 2.5 cm. it fell on a screen with an aperture of .oo3 sq. mm. The portion of the original beam that came through this travelled 3.3 cm. and) then met a screen with a slit in it, .8 mm. long and .03 or .04 mm. wide. A vacuum of about .OOOOI mm. of mercury was maintained in the entire space included in the apparatus.
114
CURRENT
TOPICS.
[J. F. I.
The slit is just at the beginning of the sharp edge of a wedgeshaped electromagnet. The tiny beam of silver atoms, after passing through the slit, moves parallel to this edge, which is 3.5 cm. long, at less than .5 mm. from it. At the further end of the edge the ray The process strikes upon a glass plate on which it forms a deposit. was continued for eight hours and even after this length of time the quantity of silver deposited was so small that a method of developWhen the magnetic ment needed to be used to bring it into evidence. field was absent, there was revealed a strip of deposit 1.1 mm. long with a width varying from .06 to .I mm. With the magnetic field In the middle of present the shape of the deposit is very different. the area there is a portion of the glass showing no deposit at all. This has the form of a section of a double convex lens taken parallel to the axis. In the direction away from the magnetic edge there is a deposit bordering the unaffected middle space and there is a similar deposit on the side toward the edge. Right opposite the edge appears “ The impressions a projection of deposit like the boss of a shield. show that the ray of silver atoms in a non-homogeneous magnetic field is divided into two parts, one of which is attracted to the edge There was of the magnetic pole while the other is repelled from it.” no trace of atoms that were neither attracted nor repelled. The attraction was stronger than the repulsion. In commenting on this highly important experiment, J. C. McLennan, in his presidential address before the Section of Mathematics and Physics of the B.A.A.S. last September, said: “ From these results it was concluded that all the silver atoms in the stream of vapor possessed a definite magnetic moment, and that while the atoms were passing through the magnetic field their magnetic axes had two distinct orientations in space.” In further interpretation of the phenomena observed this additional citation is worth while : “ One of the most surprising and interesting developments of the quantum theory is that which shows that quantum numbers determine not only the size and form of the electron is Keplerian orbits in atoms, but also the orientation of these orbits in space with regard to a favored direction such as that provided by an interatomic or by an external magnetic or electric field of force. For any arbitrary value of the azimuthal quantum number k, the simple theory shows that there are exactly (k + I ) quantum positions of the orbital plane characterized by whole numbers. For example, if k = I the normal to the orbit may be either parallel to the direction of the controlling field or at right For silver k does angles to it.” (Should this not be at 1%” to it?) equal I. Hence the atoms of this metal set themselves in one of the two possible positions and accordingly form parts of one or other of the two rays into which the original ray is divided. The two authors made a subsequent study of the rate of variation of the magnetic field and came to the interesting additional conclusion that “the magnetic moment of the normal silver atom in the gaseous state is one Bohr magneton.” G. F. S.