The Locomotive . e may convenientlycall the experimental tube), was partially filled with mercury, the space abovewhich was occupied by the water and steam whose properties were to be investi-gated. The tubes, G and H, served as pressure gages, and will be describedsubsequently. Ramsay and Young do not explain how the connections betweenthe glass tubes and the iron body were made both strong and tight, and themethod suggested in the engraving, where the tubes are supposed to be sur- I907-] THE LOCOMOTIVE. 185 rounded by masses of soft rubber tbat are strongly compressed by turning upthe iron c


The Locomotive . e may convenientlycall the experimental tube), was partially filled with mercury, the space abovewhich was occupied by the water and steam whose properties were to be investi-gated. The tubes, G and H, served as pressure gages, and will be describedsubsequently. Ramsay and Young do not explain how the connections betweenthe glass tubes and the iron body were made both strong and tight, and themethod suggested in the engraving, where the tubes are supposed to be sur- I907-] THE LOCOMOTIVE. 185 rounded by masses of soft rubber tbat are strongly compressed by turning upthe iron caps on the nozzles, may not be the one that was actually knowledge of this detail, however, is not essential to a genera! understandingof the apparatus and its mode of operation. Each of the tubes, G, H, and Ar, was carefully graduated, and its error-;of graduation and of caliber were investigated by a method similar to thatemployed by Battelli. That is, each tube was first inverted, so as to bring its. Diagram of Ramsay and Youngs Experimental Apparatus. closed end downward, and successive weighed quantities of mercury were thenpoured into it. As the volume of a given weight of mercury is accuratelyknown, the volumes included between the closed end of the tube, and thevarious graduation marks etched upon its side, could be ascertained with cor-responding accuracy, by noting the level of the mercury surface in the tube,after each successive addition. ( A process of this sort, by which the true 186 THE LOCOMOTIVE [April, volume of a tube up to any given mark is ascertained, independently of any-variations of caliber that may exist, is technically known as calibration.) As is well known, the surface of the mercury in a vertical tube like G, H,or N, is not plane and level, but is curved, with its convexity upward. In deter-mining the volume of the upper part of such a tube, when the mercury columnstands opposite a given graduation mark, it is therefore necessary to make


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Keywords: ., bookauthorhartfordsteamboilerin, bookcentury1800, bookdecade1860