The use of south as in the phrase go south stems from the 1920s (from the Oxford English Dictionary):
colloq. (orig. Stock Market). Downward or lower in value, price, or quality; in or into a worse condition or position. Esp. in to head (also go) south.
1920 Elgin (Illinois) Dairy Rep. 13 Nov., Meat, grains and provisions generally, are like Douglas Fairbanks, headed south—in other words, going down.
The reason South is correlated with down is because of its use in the standard Western set of cardinal directions:
According to the Oxford English Dictionary, the meaning of telling someone to "go west" is not related to the phrase "going south". Instead, it means:
go west, young man: used as an encouragement to seek fortune in the American West; also in extended use.
Attributed to Horace Greeley, who, according to Josiah Bushnell Grinnell, gave the latter this advice in September 1851 (see quot. 1891)
The phrase go west on its own also refers figuratively to death (as the sun sets in the West).
There is no similar idiom "go east", unless one is actually telling someone to go in the cardinal direction of east.
The direction "north" has a figurative meaning as well:
Higher; esp. in north of (a figure, cost, etc.): higher than, in excess of.
Though north and south have related meanings (higher and lower, respectively), they are used in different ways. North is usually used in respect to a give figure or amount. For example,
2001 San Francisco Business Times (Nexis) 9 Nov. 21 What's your average deal size? It's gone north of $250,000 per contract even as high as $300,000 per contract.
However, south is usually used as a general figure of speech. For example,
2003 R. B. Parker Stone Cold (2004) xl. 154 But your marriage went south and you had a drinking problem.
That being said, the two can be used both to refer to figure amounts, although in my experience this usage is rarer:
1986 Financial Times (Nexis) 5 July i. 6 With oil heading south of $10‥the London stock market today stands less than 4 per cent below its highest ever level.
1. Did "long time no see"
arrive in U.S. English from forms of pidgin English
spoken separately by both some Native Americans
and some Chinese immigrants?
The earliest recorded examples are from native Americans, but it's plausible it was used in other types of pidgin English at the same time.
2. When did this
turn of phrase first gain the recorded notice of an
American English-speaking author?
It has been recorded by American English-speaking writers in 1900. The author Raymond Chandler used it in a 1939 newspaper and 1940 book.
3. When did the phrase cross over into use by native U.S.
English speakers among themselves?
Chandler presumably helped popularise it with detective stories and film noir of the early forties.
The OED says it's a "Colloq. phr. (orig. U.S.) long time no see, a joc. imitation of broken English, used as a greeting
after prolonged separation."
Their earliest quotation is 1900 from a native American:
1900 W. F. Drannan Thirty-one Years on Plains
(1901) xxxvii. 515 When we rode up to him [sc.
an American Indian] he said: ‘Good mornin. Long
time no see you.’
Their next quotation of 1939 shows it was fully naturalised:
1939 R. Chandler in Sat. Evening Post 14 Oct. 72/4
Hi, Tony. Long time no see.
Their next is also from Chandler, in 1940's Farewell, my Lovely.
Best Answer
According to the Oxford English Dictionary, the nature of the beast first appeared in the 1600s:
John Ray's Collection of English Proverbs was a collection of proverbs from different languages, as well as a list of words, a fact noted by the title page shown here. However, it seems very possible that the phrase predates this notation. The phrase appears in a dictionary entry for nature, and the nature of the beast was used to give an example sentence.
It is possible that the phrase was well known enough that, by the time Ray compiled his list, it was an accepted idiom. However, his work is the first written usage, so we can definitely note the point at which the idiom existed. Because this is the first written usage, however, we cannot derive its origins--the phrase was written, but its precise origins were not.
That being said, the OED marks usage of beast which are related, and possibly point to the history of the phrase. In the entry of beast, two definitions are:
The phrase the nature of the beast, having been recorded in 1678, may have been pulling on the first noted definition. That is, the nature of the beast was the inherent nature of man; that deepest essence within him. The later definitions may also work (as a beast is lower than man, "the nature of the beast" is the lower qualities within a man). The old usage of the term beast would explain the origins of the phrase--it was a normal definition of beast, which literally described the inner nature of man.