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, the U. S. reached what is still its era of greatest-ever output, producing an average of 800 feature films annually, or 82 % of the global total ( Eyman, 1997 ).

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 clarifying fundamental premises in the social sciences, and defining the logical problems emergent at the borderlands of each new scientific discipline, philosophy can offer the sort of distinction that can accelerate growth in human understanding.

By the late 19th century, two problems were identified before heavier-than-air flight could be realized.

By definition it does not cover problems whose solution are unknown or have not been characterised formally.

By summer 1998, Compaq was suffering from product-quality problems.

By the autumn of 1950, financial problems had developed, and by November 1950, the six Foundations had spent around one million dollars and were more than $ 200, 000 in debt.

By the mid 17th century, numerous small Dutch and Flemish distillers ( some 400 in Amsterdam alone by 1663 ) had popularized the re-distillation of malt spirit or wine with juniper, anise, caraway, coriander, etc., which were sold in pharmacies and used to treat such medical problems as kidney ailments, lumbago, stomach ailments, gallstones, and gout.

By the end of the 1990s, he was appearing only in the occasional commercial, largely because of health problems ( in 1995, he was diagnosed with T-cell lymphoma ).

By 1976, however, he had sorted out the international travel problems, and went to Gabon instead, inspired by the book Trader Horn.

By allowing possession and retail sales of cannabis, but not cultivation or wholesale, the government creates numerous problems of crime and public safety, he alleges, and therefore he would like to switch to either legalising and regulating production, or to the full repression that his party ( CDA ) officially advocates.

By the 20th century, labour inputs were typically the most costly inputs in most industrialized societies, so focus shifted to team cooperation and dynamics, especially the early signalling of problems via a continuous improvement cycle.

By the early 1970s, operational problems on the Port Sudan-Khartoum section of Sudan Railways had resulted in inadequate supplies of petroleum products reaching Khartoum and other parts of the country.

By the late 1980s, structural flaws within the Soviet system, growing economic problems, the rise of anti-communist sentiment and the effects of the Afghan war made it increasingly impractical for the Soviet Union to impose its will on its neighbors.

By comparison, the 180 ° flat-6 boxer engine is only moderately wider than the 120 ° V6, and unlike the V6 is a fully balanced configuration with no vibration problems, so it is more commonly used in aircraft and in sports / luxury cars where space is not a constraint and smoothness is important.

By this time they had started to build a sizeable following in Manchester, and their first gig in the North of England at Clouds in Preston attracted a large audience, but descended into a riot after technical problems and friction between the bands on the bill.

By the time of the Penya Rhin Grand Prix in late June, Nuvolari's leg was finally out of plaster, but was still causing him troubles as he battled pain until he retired his Maserati with technical problems.

By 1830, because of difficult economic conditions in Britain that reduced the demand for fossils, coupled with long gaps between major finds, Anning was having financial problems again.

By 1916 the lack of co-ordination of the Army's Royal Flying Corps and the Navy's Royal Naval Air Service had led to serious problems, not only in the procurement of aircraft engines, but also in the air defence of Great Britain.

By the late 1960s and early 1970s, many planners felt that modernism's clean lines and lack of human scale sapped vitality from the community, blaming them for high crime rates and social problems.

By this account, there are no metaphysical or epistemological problems special to mathematics.

By the late 1990s new research building on Mack's insights was beginning to mature, and after 2004, the U. S. military began once again to seriously consider the problems associated with asymmetric warfare.

# By tracking who pays, and when, the distributor can see potential problems developing and take steps to reduce or increase the allowed amount of trade credit he extends to prospering or posure to losses from customers going bankrupt who would never pay for the ice cream delivered.

By this time, Niven was having serious health problems.

By 1060s, the tentative balance between the different ethnic groups within the Fatimid army collapsed as Egypt was suffering through a serious span of drought and famine, the declining resources accelerated the problems between the different ethnic factions and outright civil war began, primarily the Turks and Black African troops were fighting each other while the Berbers shifted alliance in between.

By the time he was ten, his father had financial problems.

By implication, the way to resolve some of the problems was to stabilize the political situation and to improve the economic conditions of the nation radically.