40 



thoroughly firm soap, approximately one half of the added water being 

 lost. This product was afterwards shown to contain 48 per cent of 

 water, and yet on diluting it at the same rate as the other soaps it 

 solidified on cooling, showing a very strong tendency in this direction. 



The opposite results obtained with different products of both the 

 Good and Pinner factories indicate the total unreliability of the insecti- 

 cide soaps at present obtainable and the necessity always of a prelimi- 

 nary test before using, or, better, before buying a soap in quantity, as 

 well as the very urgent need of some action which will put within our 

 reach a reliable article. 



The second examination, viz, the percentage of water contained in 

 soaps, was determined for me for eight brands by Professor Patrick, 

 of the Chemical Division, United States Department of Agriculture. 

 The samples submitted to Professor Patrick included five of the soaps 

 which remained liquid at 2 pounds to the gallon and three that became 

 solid. Eliminating the soap referred to above which contained 48 per 

 cent of water, although still a soap hard enough to cut and handle 

 easily, the per cent of water in the other soaps ranged from 9.40 in the 

 Leggett whale oil to 28.30 in the potash soap made by Good. 



The percentages of water in the soaps which were liquid in the solu- 

 tion test are as follows : 



Whale oil (Leggett ) 9. 40 



Concentrated chemical (Pinner) 11. 60 



Lye soap in bulk (Pinner) 14. 80 



Light-colored soap (Good) 22. 30 



Potash soap (Good) 28. 30 



The percentages of water in the soaps which solidified after the solu- 

 tion test are as follows : 



Tobacco chemical (Pinner) 21. 80 



Fish oil in bulk (Good) 22.90 



Fish oil in bulk (Good), treated as above described with water 48. 00 



The last sample shows that the per cent of water in soap has very 

 little to do with its remaining fluid when employed at the strength indi- 

 cated, this sample having 48 per cent water solidified, whereas the 

 whale-oil soap, having the least water (9.40), remained liquid. It indi- 

 cates also very clearly that much money may be unwittingly spent for 

 water in the purchase of soaps unless they be previously tested in this 

 direction. 



It is well known that potash tends to make a soft soap and soda a 

 hard soap in combination with oleic acid, which exists in most fats and 

 enters largely into the composition of soaps. The presence of stearin, 

 however, will have a marked influence on the quality of the soap, mak- 

 ing it harder with potash and very hard with soda. Soaps, therefore, 

 made with fats containing much stearin, such as mutton and beef tal- 

 low, and also some of the vegetable fats, will be very hard. The solu- 

 bility of soaps in water, in the above combinations with potash or soda 

 and oleates or stearates, ranges from a soap made with potash and 



