Manual of human physiology / by Leonard Hill.

  • Leonard Erskine Hill
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Manual of human physiology / by Leonard Hill. Source: Wellcome Collection.

    21/504 page 5
    centimetre, and that is the standard of length. Thus in the metric system the measures of length, volume, and weight are directly connected with each other. The value of this is seen at once, when you wish to make solutions of a certain strength. To make a one per cent, solution of common salt, weigh out one gramme of salt, mix it with one hundred cubic centimetres of water, and the required solution is obtained. Weight and volume. Weight is our best means of comparison since weight is not altered by temperature, while volume is. A pint of hot water, if allowed to cool, will shrink in volume and become less than a pint, but the weight of the water will not alter. Carry out the following experi- ments : — 1. Obtain a metre measure-tape, and with that measure your own height. 2. Find how many millimetres there are in one inch. Buy a 2;raduated measure-e^lass con- r. ^ ^ ^. . ^ 1 1 Fig. 3. Balance to tammg loo cubic centimetres, tind how weigh up to so grms. many cubic centimetres of water there are f^^l Gaiienkamp in a pint. 4. Obtain a set of gramme weights. Some French centime (==one gramme) and ten centime ( = ten gramme) bronze coins from a money-changer will do. By means of an ordinary letter- balance find out how many grammes it takes to balance an ounce. For exact scientific work far more delicate balances are used, by means of which the weight of any substance can be determined to the thousandth part of a gramme. 5. Weigh the empty measure-glass. Place exactly 50 cubic centimetres of hot water within it. (To read the volume of water correctly place your eye on the same level as the top of the water.) Weigh the glass and the water within it, and determine the weight of the water by subtracting the weight
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