A 10 per cent, solution means ten parts of substance in one hundred of solution, and the same for other percentages.

The term "parts" in formulas generally means parts by weight, whether referring to liquids or solids; for instance: 1=10, "1 part by weight in 9 parts of liquid "means 1 grain or 1 gramme or 1 ounce or 1 pound, to be dissolved in 9 grains, grammes, ounces or pounds of water, fluid measure, or any other liquid.

Solid 1 part,....1

Liquid 9 parts, .............................9

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Altogether 10 parts or, multiplied by 10:

Solid 10 parts,...10

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Altogether.....100 parts or, 10 per cent. solution=10 parts of substance in 100 of solution. 1=100, " 1 part by weight in 99 parts of liquid" means the same. Solid 1 part, .... 1

Liquid 99 parts,...99

Altogether 100 parts or 1 per cent. solution=l part substance in 100 of solution.