EXPERIMENT STATION BULLETINS. 263 



dilution and will have less to carry. Though not very important this point 

 is worthy of consideration. It were better if the emulsion upon standing 

 could always be diluted, even though cold, with cold water either soft or 

 hard. With some kinds of hard soap this is quite impossible with all desira- 

 ble emulsions so far as we have tried them. Yet as all will do so upon heat- 

 ing them, or heating the water used to dilute them, the objection is not 

 serious. Often an emulsion upon standing forms a fibrous or curdy mass, 

 which upon dilution becomes stringy or granular, does not liquefy, and 

 rises to the top. . Immediate dilution upon making the emulsion, or heat- 

 ing, either the emulsion or diluent, at any time subsequent when we wish 

 to dilute it, prevents all such trouble. Thus this is no positive evil, only 

 a matter of inconvenience. 



In making an emulsion, violent agitation is positively required. Simply 

 stirring with a spoon or stick is not sufficient. The best method is to use 

 a pump and force the liquid back into itself, through a small nozzle This 

 stirs the liquid very violently and, in two or three minutes, we obtain a 

 thick creamy substance, which is the emulsion. The cheap dollar pumps 

 work admirably and are all that is required. Any pump that will do for 

 spraying may be used. That an emulsion may be easily made, and per- 

 manent after dilution with hard water, it is necessary to have an excess of 

 water. Thus a diluted, and often an undiluted emulsion, will separate 

 from the soap solution; but the kerosene oil never separates, it always 

 remains in an emulsion which rises above the soap solution. This is no 

 objection, as by shaking the diluted and warming when necessary, diluting 

 and shaking the undiluted, all will mingle or mix in one uniform liquid 

 and remain mixed for some time before the emulsion again rises to the 

 top. The separation of free oil is a fatal objection; the separation of the 

 emulsion from an excess of soap solution is no objection. 



Several formulas for making emulsions have been recommended, which 

 we will give in order of excellence as we find them and the reasons for and 

 against each. We advise all to try each one, as it takes but little time, 

 then the advice and suggestions here given will be appreciated. 



NO. 1, SOFT SOAP AND KEROSENE EMULSION. 



Dissolve one quart of soft soap in two quarts of boiling water. Remove 

 from fire and, while still boiling hot, add one pint of kerosene oil, and 

 immediately agitate with the pump as described above. In two or three 

 minutes the emulsion will be perfect. This should be diluted by adding 

 an equal amount of water, when it is ready for use. This always emulsi- 

 fies readily with hard or soft water; always remains permanent, for years 

 even; and is very easily diluted, even in the coldest weather, and without 

 any heating. In this last respect it has no equal, so far as we have exper- 

 imented. The objections to it are: We can not always procure the soft 

 soap, though many farmers make it, and it is generally to be found in our 

 markets. It occasionally injures the foliage, probably owing to the caustic 

 properties of the soap. We have used this freely for years, and never saw 

 any injury till the past season. In case of any such trouble, we may use 

 only one half the amount of soap — one pint instead of one quart. It works 

 just as well, and we have sometimes recommended this proportion. The 

 soap itself, however, is an excellent insecticide, and we have preferred the 

 stronger solution as given in the formula above, unless it injures foliage 

 which will rarely be the case in a one fifteenth kerosene mixture. Again, 



