funtofil (Виталий Томчик) (funtofil) wrote,
funtofil (Виталий Томчик)

(290) Эталонные гири. Reference weights

В сентябре 2014 года исполнялось 125 лет с момента появления на свет международного прототипа килограмма. Решение о создании эталона было принято на Генеральной конференции мер и весов 7-9 сентября 1889 года в Париже.

Он хранится в Международном бюро мер и весов около Парижа и представляет собой цилиндр диаметром и высотой 39,17 мм из платино-иридиевого сплава (90% платины, 10% иридия). Такой состав выбран из-за высокой плотности платины, так что эталон можно сделать относительно маленького размера: меньше спичечного коробка по высоте.

Масса международного прототипа примерно соответствует 1 литру воды при температуре 4°C, а его вес зависит от высоты над уровнем моря и силы гравитации.

Когда изготовляли международный прототип, вместе с ним сделали 40 копий из того же платино-иридиевого сплава. Их разослали по национальным бюро мер и весов в разных странах, чтобы учёным не приходилось обращаться к основному эталону каждый раз для проведения измерений.

Национальные прототипы сверяют с основным прототипом каждые 40 лет. Последняя проверка проходила в 1989 году, и тогда максимальная разница в весе составила 50 микрограммов. Эти девиации беспокоят учёных. Они понимают, что масса конкретного образца изменяется со временем из-за физических повреждений и появления прочих артефактов.

Разделенный или параллелепипедный килограмм.
OFFICIAL FRENCH STANDARD WEIGHTS -- THE "PARALLELOPIPED KILOGRAM", very early 19th century. Contained in its 4" x 4-1/2" x 1-1/8" (10 x 11 x 3 cm) fitted wood box are the subdivided elements of a kilogram, specifically brass weights of 500, 200, 100, 50, 20, 10, and 1 gram. Each rectangular weight has an adjustment plug, and is marked with its weight value, plus a host of standardization marks, including variously an image of a balance beam, the number 47, the city (Limoges), the "all-seeing-eye" above an "L," the letter "H," a crowned eagle, and letter certifications running continuously (except no "J") from A through K. Condition is very fine and complete but for tweezers and a few of the smallest weights (present are 991 out of the full 1000 grams). The "parallelopiped kilogram" was published by chemist Claude Antoine Prieur in 1797, in the Annales de Chimie. He devotes eight pages to their description and advantages, and recommends those made by Fortin. The weights could be purchased at the Bureau of Weights and Measures, on rue Dominique in Paris. The present set was made for official use in the town of Limoges, and bears certifications through the first quarter of the 18th century. Following Pommier (in recent issues of Le Systeme metrique), we find that for primary standards the balance beam mark was used 1801 - 1840, the crowned eagle 1808 - 1812, and the sequential year letters starting with A for 1802 (or a couple of years later in some of the provinces). A very rare survival, this is an important standard set from the early years of the metric system. (8379) $3800.
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A highly collectible set of standard or reference weights and measures - Victorian and earlier brass / copper-alloy engineering with aesthetic appeal. Historical and family research can be based on manufacturers' names, Government stamps, paper ephemera, and even metal detector finds!
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Bermuda, Standard Imperial Weights 1888

This full set of Imperial Standard Weights were made in Britain in 1888 by V. & R. Blakemore of London for the Colony of Bermuda. The set consists of 11 weights ranging from the 1 ounce up to the 56 pound. They would have been verified for accuracy and certified as indicated by the various verification marks and the indenture number.

Each weight is engraved with; "Standard Weight", "Bermuda", "1888", "C^A", "V.& R. Blakemore, London" (the maker), a crown and an indenture serial number 2025.

Engraved on the handle of each is the weight designation ( 1, 2, 4, 8 ounces and 1, 2, 4, 7, 14, 28, 56 pounds. Pictured here is the 56 pound weight.

Verification marks include a stylized crown over VR., and the London

Gate' mark dated 1888. This set of weights would have been used by weights and measures inspectors and would be the standard that weighing apparatuses being used in the trade would have to measure up to. It is likely, given the small size of Bermuda, with a relatively small population, that only one set of standard weights were required.
Tags: #гирька, #гиря, #эталонные гири

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