38 Kansas Academy of Science. 



definite amounts of gases, which may be drawn from a container 

 for any experiment. Such gases as illuminating gas, sulphur 

 dioxide, carbon dioxide, hydrogen sulphide, etc., have been em- 

 ployed. Insects confined within the chamber of the apparatus and 

 subjected to the influence of various insecticides can be watched 

 and timed so that the relative value of toxic action can be readily 

 estimated. 



Hamilton and Lowe have tabulated in their report the coeffi- 

 cients for thirty-eight different insecticides, including such articles 

 as creosote, naphthalene, kerosene, oil of turpentine, hydrocyanic 

 acid, and many powders. 



Our own experiments have shown that a solution of carbolic 

 acid, from 6 to 7 per cent, acts very powerfully by the contHct 

 method, but much less powerfully as a fumigant; it has ^/so the 

 strength of sulphur vapor, for example. It may be said of many 

 of the commercial plant powders that they are exceedingly weak as 

 compared with sulphur. A powder known as "bugbane" {Cimi- 

 cifuga raceviosa) has long been considered efficacious. Our ex- 

 periments with it, however, tend to show that this drug has been 

 greatly overestimated in its toxic properties toward insects. Pow- 

 dered cimicifuga seemed to be devoid of insecticidal properties. 

 Crickets kept in contact with the powdered drug for hours showed 

 no toxic effect. 



For the chemical valuation of the well-known insect powder, 

 H. Linke has suggested a method. ( See Chem. Abstracts, vol. 6, 

 No. 23, p, 3493.) 



The following articles compounded with insecticides require to 

 be guaranteed under the national insecticide act, when sold for in- 

 secticidal purposes: 



Acid, carbolic, cryst. Insect powder, foreign. 



Acid, carbolic, crude. Naphthalene. 



Acid, cresylic. Nitrobenzene. 



Acid, muriatic. Oil citronella. 

 Acid, nitric. , Oil camphor. 



Acid, sulphuric. Oil peppermint. 



Ammonia, stronger. Paris green. 



Arsenic, white. Phosphorus. 



Borax. Potassium cyanide. 



Camphor. Potassium permang. 



Carbon bisulphide. Potassium carb. 



Carbon tetrachloride. Potassium sulphide. 



Copper sulphate. Quassia. 



Formaldehyde, sol. of. Rosin. 



Hellebore, white. Sulphur, grd. or lump. 



Iron sulphide. Sulphur, refined. 



Lead arsenate. Turpentine. 



London purple. Whale oil soap. 

 Iron sulphate. 



