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Densities of liquid argon have been measured along the saturation boundary 84 K to nearly its critical point by a method based on Archimedes principle. The estimated accuracy of these measurements is 0.028% at the low end of the temperature range and 0.094% near the critical point.

A simple microscopic deduction of Archimedes' principle as applied to gases is given in terms of the kinetic theory, and some conventional explanations of barometric effects are queried.

Densities of liquid oxygen and liquid nitrogen have been measured along the saturation boundary from 80 K to near the critical points by a method based on Archimedes principle. The estimated accuracy of these measurements is 0.033% at the low end of the temperature range and 0.175% near the critical points.

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This paper presents a little knew method for determining soil moisture supported on the famous Archimedes principle. It is suggested also a modification to the original method for making it convenient to the use in relation to soluble fertilizers. Finally, this paper presents a simplification to the original method in order to make it useful to the determination of moisture in granular fertilizers, seeds and soils without immersion of them. No presente trabalho é apresentado um método pouco conhecido para avaliação da umidade de um solo, baseado no princípio de Arquimedes. Nele também se sugere uma modificação ao método para adaptá-lo ao uso em relação a fertilizantes solúveis. Finalmente, este trabalho contém uma simplificação do método original que permite a dosagem da umidade em fertilizantes granulados, sementes e solos sem proceder-se à imersão.

This chapter reviews the results of certain basic mechanics principles. A body is recognized as possessing mass in as much as it resists change of motion, that is, it requires a force to be exerted on it to move it, from rest, or to change its velocity when in motion. If a force acts through a distance in its own direction, then the product is a measure of the work done by the force. The chapter discusses the basic principle of energy. Energy is defined as that which is required for the performance of work. Power is defined as the rate of performance of work. The three states of matter are solid, liquid, and gas. The measure of the quantity of matter contained in unit volume of a substance, that is, the mass per unit volume, is called the density of the substance. The Archimedes' principle states that the apparent loss of weight suffered by a body, partly or completely immersed in a fluid, is equal to the weight of the fluid displaced by the body. Graham's law of gaseous diffusion states that the rate of diffusion of a gas through a porous membrane is inversely proportional to the square root of its density. Experiments performed over a period of time have shown that some diffusion occurs at solid surfaces in contact but to an extremely slight extent.

SummaryThe copper sulfate method of determining the specific gravity of blood has been applied to fresh tissues. A number of factors influencing the determinations have been studied. Comparison of this method with that based on Archimedes principle have shown the copper sulfate method to be decidedly superior.

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When it is necessary to determine the volumes of individual sediment grains or fossils the hydrostatic weighing method based on Archimedes' principle is the simplest, and probably the most accurate method available. Any simple weighing instrument can be used without constructing special devices.

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A weighing lysimeter is described which operates on Archimedes principle and which has been used to obtain continuous values of evapotranspiration from an irrigated pasture. Some errors in evaluation of evapotranspiration by means of a lysimeter are discussed.