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 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 counting the number of stalls and urinals I attempted to form a loose estimate of how many men the hall would hold at one time.

By applying this general principle, a great number of complex compounds of osmium, ruthenium, iridium, and rhenium, with triphenylphosphine, triphenylarsine, and triphenylstibine have been obtained in this laboratory during the past few years.

By 1907 the number of undergraduates had risen to 1,107.

By its inclusion the order has grown enormously in number of species.

By making the mass number of soldiers blend within the landscape / painting, it shows that he believed that the usage and depiction of landscape was just as significant as a historical event, such as a war.

By the 18th century an increasing number of new plants had arrived in Europe from newly discovered countries and the European colonies worldwide and a larger number of plants became available for study.

By measuring the mean squared displacement over a time interval along with the universal gas constant, the temperature, the viscosity, and the particle radius, Avogadro's number can be determined.

By this point their number of MPs was severely depleted.

By now the rebel forces were said to have numbered 230, 000, however, this number should be treated with scepticism — Dio's account is known only from a late epitome, and ancient sources commonly exaggerate enemy numbers.

By the late 1950s, the once-prosperous port area of downtown Manhattan was occupied by a number of dilapidated shipping piers, casualties of the rise of container shipping which drove sea traffic to Port Elizabeth, New Jersey.

By attempting to predict which branch ( or path ) a conditional instruction will take, the CPU can minimize the number of times that the entire pipeline must wait until a conditional instruction is completed.

By the mid-20th century, the number of examples of people skipping stages, such as going from hunter-gatherers to post-industrial service occupations in one generation, were so numerous that 19th-century evolutionism was effectively disproved.

By convention, a calendar year consists of a natural number of days.

By far the most visible and obvious power of many modern central banks is to influence market interest rates ; contrary to popular belief, they rarely " set " rates to a fixed number.

By the end of 2005, the number of telephone main lines in use totaled 7, 851, 649.

By the time of Howard's suicide in 1936, he had written 21 complete stories, 17 of which had been published, as well as a number of unfinished fragments.

By contrast, the album had limited success in the US, only reaching number 83 on the Billboard 200 Album Chart.

By reducing the number of tracks used ( and thus the capacity ), Commodore could further reduce cost-in contrast to the double-density drives used e. g. in IBM PCs of the day which saved 180 KB on one side ( by using a 40-track format ).

By 1968, the number of dance clubs started to decline ; most American clubs either closed or were transformed into clubs featuring live bands.

By connecting to the Forgotten Tribe's settlements ( represented by number tokens ), players may earn cloth tokens when the number token for the Forgotten Tribe's villages are rolled.

By contrast, integrated circuits packed a large number — often millions — of tiny electrical components, mainly transistors, into a small chip around the size of a coin.

By the early 18th century, other publishers began to issue collections of dances as well ; a conservative estimate of the number of dances in the English style published between 1651 and 1810 would run to around 20, 000.

By inserting the energetic definitions of the ionization potential and electron affinity into the Mulliken electronegativity, it is possible to show that the Mulliken chemical potential is a finite difference approximation of the electronic energy with respect to the number of electrons., i. e.,