174 THE MONTHLY BULLETIN. 



lime soap that floats on the surface of the water as a sticky, greasy 

 mass. In soap making this insoluble matter mixes with the soluble 

 part, making- a poor grade of soap. 



Hardness of water may be either "temporary" or permanent. The 

 former is generally applied to the presence of bicarbonate of lime in 

 solution in the water, while "permanent" hardness is due to the pres- 

 ence of mineral salts in the water, which can not be removed by boiling 

 or a simple chemical treatment. 



Boiling the water will overcome temporary hardness as will also the 

 addition of (juick lime (calcium oxide). By either method the soluble 

 bicarbonate is converted into the normal carbonate, which is insoluble. 

 The insoluble lime settles out and the clear water may be poured off. 



The permanent hardness of water is not affected by boiling but must 

 be treated with some chemical that will unite with the minerals held in 

 solution in the water, and cause them to settle out ; afterwards the 

 clear water may be poured off. The ordinary lye of commerce, or lime, 

 may be used, but with lime it is believed that a slightly soluble salt 

 (calcium hydroxide) is formed, which would also give trouble. Car- 

 bonate of soda (sal soda) is preferable, as this forms an insoluble salt 

 that is precipitated out ; but even this form would be of no avail in 

 the treatment of alkali water. Soda ash phosphate may give better 

 satisfaction than sal soda (carbonate of soda) as it will dissolve in 

 water much quicker than the carbonate form. 



If there is any doubt as to the quality of the water used it is best to 

 have a chemical determination made as a guide to further work. 



MANUFACTURE OF SOAP. 



Soap making is an art rather than a science, and proficiency comes 

 only through long practice. Soft soap is considered easier to make than 

 the hard, but even with this form the varying factors of water, oil and 

 alkali are often difficult to adjust. On a large scale steam may be used, 

 but as the cooking period is not long and a very high temperature is 

 unnecessary except in cresol mixtures, elaborate preparation is unneces- 

 sary. 



Fish Oil Soap. 



FORMULA. 



Fish oil ,1 gallons 



Caustic potash 4 pounds 



Water 8 gallons 



This soap, used at the rate of one pound to eight gallons of water, 

 gives good results against aphids (plant lice). Use a large kettle that 

 will allow^ for frothing during the boiling. In this dissolve the caustic 

 potash in hot water, then add the oil and boil until the soap is formed, 

 which is shown by a light brown color. This stage is usually reached 

 within a few minutes. The mixture should now be somewhat stringy 

 when dipped up with the paddle; dropped into cold water a clear 

 solution with no globules of oil floating on the surface results. A little 

 of the melted soap may be dropped on a clean piece of glass and 

 allowed to harden ; when cold it should be almost clear, with no free oil 

 or grease. After this stage has been reached it simply remains to boil 

 the soap down to the proper consistency. If there is any free oil after 

 the soap is formed a little more alkali dissolved in water should be 



