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Ch. 6: Physical Properties

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say 50 or 100 c.c. When filled up to the top of the hole at a definite temperature, it may be used to determine the specific gravity of a substance in the form of loose granular material which can be had in sufficient quantity. This method involves three or four weighments in the balance and is not very much used. It is accurate but slow, and may be used with powdered material, fragments and cut stones. An appreciable amount of material must be used.
The weight W of the empty, clean and dry bottle is first determined with a Chemical balance: The substance which must be quite dry is placed in the bottle so as to fill about half or one-third of the volume of the bottle. The weight is again taken. The weight of the
substance is
The bottle is now nearly filled with distilled water and gently shaken so as to dislodge all the air bubbles. It is next completely filled up with distilled water, its outside well dried and again weighed. Let this weight be grammes. The substance is now removed from the bottle, which is again filled with distilled water and weighed after drying the exterior. Let this begrammes.
The difference between (2) and (3) above is the weight of water displaced by the solid substance—the volume of the displaced water being equal to that of the substance.
The specific gravity of the substance
To ensure greater accuracy by avoiding error due to air films after introducing the substance and water, the latter
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Ch. 6: Physical Properties Page of 187 Ch. 6: Physical Properties
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