Retrograde motion

Ruckwkrtsbewegung, /. retrograde motion. Riickweg, m. return path, ruckweise, adv. by jerks intermittently, riickwerfen, v.t. throw back reflect, riickwirken. v.i. react. 

There is one immediate problem with the m n classification scheme. It concerns the possibility of retrograde motion, i.e. the possibiUty that one of the angles 0 or 02, or both, do not increase monotonically while traversing the periodic orbit. In this case, two different periodic orbits may end up with the same m n label. It is currently not clear whether this situation can occur. A careful study has to be based on the equations of motion (10.3.3). 

Triton is of special interest to scientists because of a number of unusual characteristics. In the first place, it is the only satellite in the solar system to revolve around its parent planet in a retrograde motion—that is, in a direction opposite to that of the planet s rotation. In addition, it is only one of three bodies in the solar system (Earth and Titan being the others) with an atmosphere consisting primarily of nitrogen gas. Triton s atmosphere is very thin, with a surface pressure of only 14 microbars, about 0.0014 percent that on Earth. Also, Triton is the coldest body ever measured in the solar system, with a surface temperature of 38 K (- 235" C). At that temperature, nitrogen is frozen, so that Triton s atmosphere consists primarily of thin clouds made of nitrogen ice and the surface is covered with a thin layer of nitrogen frost. 

I recommend paying attention to the retrograde motion of the outer planets under only two circumstances ... 

Retrograde motion Orbital or rotational motion that is clockwise as seen from north of the ecliptic. For example, Triton is in retrograde orbit around Neptune and Venus is in retrograde rotation. 

Orbital period in units of earth days. An R following the value indicates a retrograde motion. 

Philof. Tranf. v. 59. p. 392. and as no other veflels open intoit be-lides ihcfe and ihe ureters, it feems evident, that the unnatural urine, produced as above defcribed, vhen the ureters were tied, or the kidneys obliterated, was carried into this bladder by the retrograde motions of the urinary branch of the lymphatic fyftem. 

The phaenomena of many difeafes are only explicable from. the retrograde motions of fome of the branches of the lymphatic fyftern as the great and immediate flow of pale urine in the beginning of drunkemiefs j in hyfteric paroxyfms j from being expofed to cold air 5 or to the influence of fear or anxiety. 

Hence we underhand the ufe of vomits or purges, to thofe who have fwallowed either contagious or poifonous materials, even though exhibited a day or even two days after fuch accidents, namely, that by the retrograde motions of the lacfleals and lymphatics, the material hill arrelted in the mefenteric, or other glands, may be eliminated from the body. 

Hence the fluids derived from increafed fe< retlons are readily diftinguifned from thofe originating from the retrograde motions of the lymphatics thus an increafe of heat either in the difeafed parts, or difFufed over the whole body, is perceptible, when copious bilious ftools are confequent to an inflamed liver 5 or a copious mucous falivation from the inflammatory angina. 

When chyle is obferved in ftools, or among the materials ejected by vomit, we may be confident it muft have been brought thither by the retrograde motions of the la leals for chyle does not previoufly exift amid the contents of the intef-tines, but is made in the very mouths of the lafteals, as w as before explained. 

The following experiment, at firft view, would feem to invalidate this opinion of the retrograde motions of the lymphatic veflels, in fome difeafes. 

The experiment therefore above related upon the lafteals of a dead pig, which were included in a ftrift ligature, proves nothing as it is not the quantity, but the kind of ftimulus, which excites the lymphatic veflels into retrograde motion. 

XL The Caiifes ivh tch induce the Retrograde Motions of Anhnnl Vef feis and the Medicines by which the Natural Motions are rejlored. 

But as the retrograde motions of the ftomach, oefophagus, and fauces in vomiting are, as it were, apparent to the eye j we hall confider this operation more minutely, that the fimilar operations in the more recondite parts of our fyftem may be eafier underftood. 

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