TiiK MoN'riii.v li^l.I,K■^IN^ 17:-5 



oasteni coa.sl. X'cry litllc ^cimiiic \\li;ilc oil is now used in .soap 

 inakiiiii-. The [ji'iiicipal sources of our lish oil ai'c the waste from fisli 

 canneries and fertilizer factories, the oil bein<i- i)ressed out of the cooked 

 fish, then heated to drive off the water and purified, if a high grade 

 oil is desired. Fish oil generally sells at 26 to 30 cents a gallon whole- 

 sale. 



Tallow or any waste fat may be substituti'd wJioUy or in part for 

 oil. This makes a harder soap than oil but is not considered as valuable 

 for insecticidal purposes. 



Kosin has the same jiroperties as the fats of uniting with alkalies to 

 form a soluble soap, which is darker in color but lathers more freely 

 and is supposed to have good penetrating qualities. By reason of the 

 cheapness of rosin its use will decrease the cost of the soap materially, 

 and if desired it may be substituted up to one-third or more of the oil 

 or fat used. Rosin soap is considered more active as an insecticide, but 

 should be used with care on delicate plants. 



Insecticidal soaps are usually soft soaps, but may vary in consistency 

 from a hard cake slowly soluble in cold water to a liquid which dis- 

 solves almost instantly. It is possible to make soft soaps from soda 

 but potash is most frequently employed. By the latter method the 

 waste lye and other impurities are retained in the soap, making it more 

 caustic. If soda is used, a caustic liquid containing waste lye and 

 crude glycerine settles to the bottom, the soap rising to the surface. 

 For this reason the soda soap is harder and less alkaline, as it has been 

 largely freed from the waste alkali and glycerine. Besides, the potash 

 soaps absorb water while the soda soap gives off moisture when exposed 

 to the air, as is shown by the salt^ crystallizing on the surface of the 

 soap. 



The caustic form of potash or soda is generally used in soap-making, 

 although the carbonate form may be used by boiling longer. During 

 the process of boiling the alkali combines with the oil or fat to form 

 soap, or "saponifies" the fat. as it is called. By the action of the 

 alkali on the oil the latter is broken down into a fatty acid and 

 glycerine, the acid combining with the alkali, the glycerine being a 

 waste product. Caustic soda may be readily obtained in the form of 

 "concentrated lye," but this, if exposed to the air, will absorb enough 

 water to dissolve itself, being partially converted into the less caustic 

 carbonate form, as will also caustic potash, hence these chemicals should 

 be left in the original package until ready to use. Potash is not as 

 easy to obtain as soda and is more, expensive ; much of the so-called 

 potash lye is mostly soda and is unsuited for making soft soaps. 

 Laundry supply houses generally carry good grades of crude caustic 

 potash, which retails in snuill amounts for eight or ten cents a pound. 

 Potash will not saponify as much oil or fat as soda, the proportion being 

 about five to seven. 



It is possil)le to substitute soda for potash up to one-fourth or one- 

 fifth the amount of alkali, but this should only be attempted after 

 careful experimenting. 



Hard water used in soaj) making has the same effect as when making 

 up a spray solution or snap suds; the lime and magnesia salts ])rese]it 

 in the water In-eak down the soluble potash soap and form an insoluble 



^Florida Report for 1911-12. 

 3—23219 



