1970 Gene Switches

“How are genes managed? All cells should be capable to flip their genes on and off. For instance, a bacterial cell might have completely different enzymes with a purpose to digest a brand new meals supplied by a brand new setting. As a easy virus goes by its life cycle, its genes perform sequentially, directing a collection of timed occasions. As extra complicated organisms develop from the egg, their cells swap 1000’s of various genes on and off, and the switching continues all through the organism’s life cycle. This switching requires the motion of many particular controls. Through the previous 10 years one mechanism of such management has been elucidated in molecular phrases: the management of particular genes by molecules referred to as repressors.—Mark Ptashne and Walter Gilbert”

Gilbert was the co-winner of the 1980 Nobel Prize in Chemistry for his work on nucleic acids.

1920 Voice Amplification

“The loud-speaking phone system which has been positioned within the Coliseum at Chicago has been in strategy of growth for about ten years. The work was principally achieved within the laboratory on one of many busiest and noisiest water-front streets in New York. Amidst all of the rattle and bang of a thousand groups and motor vehicles pounding the stone pavement, teamsters have been startled to listen to an odd voice, apparently near their ears, intentionally and clearly reciting some rhyme like ‘Hickery, dickery, dock, the mouse ran up the clock.’ These teamsters may hardly see the horn on the roof of the lofty laboratory constructing, nor guess that checks have been being made which might facilitate the nomination of a presidential candidate.”

1870 Machine Age

“A single institution on this metropolis—the Singer Stitching Machine Firm—seems 5 hundred stitching machines per diem. The works are run evening and day.”

Wired for Magnificence

“The Allegheny Bridge at Pittsburgh: We imagine we categorical a common opinion amongst engineers and designers once we say that the bridge which kinds the topic of our engraving this week is among the most elegant buildings of its class on this continent. Nothing can exceed the grace of its define when seen from a good perspective. This stunning bridge was designed and erected in 1860, by the late John A. Roebling.”

The Sixth Road Bridge was demolished in 1892 to make method for a extra strong construction able to withstanding fashionable site visitors.

Bridges: An “Index of Civilization”

1921: Overly costly design for the longer term George Washington Bridge spanning the Hudson in New York Metropolis. Credit score: Scientific American, Vol. CXXIV, No. 23; June 4, 1921

The engineering ability to construct bridges throughout pure obstacles speaks volumes about humanity’s capability to facilitate future journey wants. Neolithic wooden walkways above marshes in England date again some 6,000 years. Wooden gave technique to stone, then iron. The provision of low-cost metal from the Bessemer course of within the late 19th century opened up a brand new period of bridge constructing: sleek metal kinds spanned better and better distances. In November 1921 an article famous that bridges mark “the progress of mankind within the artwork of building, thought-about as an index of its civilization and tradition.” Immediately the longest bridge—over canals, rice paddies and lakes—is 102 miles lengthy and carries the Beijing-Shanghai high-speed rail hyperlink.

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