By the 1920s, each state in the United States had passed public laws that stipulated a certain day to be Arbor Day or Arbor and Bird Day observance.

By the late 1920s Potter and her Hill Top farm manager Tom Storey had made a name for their prize-winning Herdwick flock.

By the 1920s, composers of Tin Pan Alley and Broadway used ballad to signify a slow, sentimental tune or love song, often written in a fairly standardized form ( see below ).

By the late 1920s, New York writers other than Fitz Gerald were starting to use " Big Apple " and were using it outside of a horse-racing context.

By the 1920s, the emerging middle and working classes were powerful enough to elect a reformist president, Arturo Alessandri Palma.

By the 1920s, many newspapers had a comics page on which many strips were collected together.

Additional milieu were provided by Chaosium with the release of Dreamlands, a boxed supplement containing additional rules needed for playing within the Lovecraft Dreamlands, a large map and a scenario booklet, and Cthulhu By Gaslight, another boxed set which moved the action from the 1920s to the 1890s.

By the early 1920s, unit operations became an important aspect of chemical engineering at MIT and other US universities, as well as at Imperial College London.

By the late 1920s, Al Capone and the Mob were inspiring not only fear, but piquing mainstream curiosity about the American underworld.

By the 1920s Lewis Fry Richardson's interest in weather prediction led him to propose human computers and numerical analysis to model the weather ; to this day, the most powerful computers on Earth are needed to adequately model its weather using the Navier – Stokes equations.

By the 1920s, the idea of an Israelite conquest of Canaan-the story of the book of Joshua-was not supported by the archaeological record.

By the 1920s, Hearst, was the owner of a chain of newspapers from coast to coast.

By the 1920s, the diatonic harmonica had largely reached its modern form.

By the 1920s however the Senate had lost much of its original influence, and hence no sitting senator had been known to have serious aspirations of becoming prime minister whilst remaining in the Senate.

By the 1920s the number of cars had soared to 60, 000.

By the early 1920s, however, the inherent limitations of this type of engine had rendered it obsolete, with the power output increasingly going into overcoming the air-resistance of the spinning engine itself.

By the 1920s psychoanalysts assumed that homosexuality was pathological and that attempts to treat it were appropriate, although psychoanalytic opinion about changing homosexuality was largely pessimistic.

By the late 1920s the resistance movement against colonial rule had gathered widespread support during the mistreatment of the Samoan people by the New Zealand administration.

By the late 1920s, however, those employing only optical and electronic technologies were being explored.

By the late 1920s, economic performance had stabilised, but the overall situation was disappointing, for Britain had clearly fallen behind the United States and other countries as an industrial power.

By the 1920s, however, this boisterous folksiness had diminished.

By the end of the 1920s Corbusier was already an internationally known architect.

By the 1920s, the British Government were seeking a replacement for their book code systems, which had been shown to be insecure, and which proved to be slow and awkward to use in practice.

" By the 1920s, Birmingham was the 19th largest city in the U. S and held more than 30 % of the population of the state.

By 1889, the U. S. output of steel exceeded that of the UK, and Carnegie owned a large part of it.

" By then, the U. S. and U. K. had transparently destroyed all their bioweapons stockpiles.

By that time, the majority of black people were U. S .- born, so use of the term " African " became problematic.

By virtue of its extensive biotechnology sector, its numerous major universities, and relatively few internal barriers, the U. S. has progressed a great deal in its development of BME education and training opportunities.

By December 1981, however, the U. S. had already begun to support armed opponents of the Sandinista regime.

By 1982 the stagnation of the Soviet economy was obvious, as evidenced by the fact that the Soviet Union had been importing grain from the U. S. throughout the 1970s, but the system was so firmly entrenched that any real change seemed impossible.

By 1959, the company had dealers across the U. S. and began selling the 310 ( known as Bluebird domestically ).

By the time DDT was introduced in the U. S., the disease had already been brought under control by a variety of other means.

By the time mass applications for wireless Internet had emerged, and the U. S. had opened up to DECT, well into the new century, the industry had moved far ahead in terms of performance and DECT's time as a wireless data transport had passed.

By studying the spectral properties of the linear operator U it becomes possible to classify the ergodic properties of Φ < sup > t </ sup >.

By the time it closed in 1954, twelve million immigrants had been processed by the U. S. Bureau of Immigration.

* 1819 – By the Adams-Onís Treaty, Spain sells Florida to the United States for five million U. S. dollars.

By 1794, after Washington ordered the protesters to appear in U. S. district court, the protests turned into full-scale defiance of federal authority known as the Whiskey Rebellion.

By the mid 19th century, the South, The city of New Orleans in particular, being situated as a key to commerce on the Mississippi River and in the Gulf, had become the largest U. S. city not on the Atlantic seaboard and the fourth largest in the U. S. overall.

By the war's end, the U. S. government had obtained control of all of Cuba from Spain.

By this time, the U. S. Marines had been issued the modern tripod-mounted M1895 Colt-Browning machine gun in 6mm Lee Navy, which they employed to defeat Spanish infantry at the battle of Cuzco Wells.

By 1969, there were dozens of homophile organizations and publications in the U. S, and a national organization had been formed, but they were largely ignored by the media.

By May 1946 the removal of machinery had ended, thanks to lobbying by the U. S. Army.

By contrast, the U. S. admitted more than 100, 000 Vietnamese refugees for resettlement during the Vietnam War.

By 1914, the problem had grown to the point where an estimated one U. S. citizen in 400 ( 0. 25 %) was addicted to some form of opium.

By replacing the M1114, M1116, and earlier armored HMMWV types with a single model, the U. S. Army hopes to lower maintenance costs.

By contrast, a number of Irish people abroad converted to Asian religions and played significant roles in anti-colonial revival movements, such as the Irish Buddhist monk U Dhammaloka (? Laurence Carroll?