128 PROCEEDINGS OF THE AMERICAN ACADEMY. 



mation of the amount of volatile compound formed in this experiment 

 is subject to too many chances for error to make it of any value except 

 as a means of throwing light on subsequent work. The main fact of 

 the formation of a volatile compound is proved, though the mode of 

 formation is not shown, and its applicability is not extended to the 

 particular question at issue. 



Here again has Hamberg given us results which are trustworthy, 

 and his two experiments are the only ones thus far in this historical 

 sketch against which valid objection may not be raised, though in 

 regard to the second I can oidy repeat what I have said of the first as 

 to absence of detail in the method. 



Hamberg, assuming the volatilization to be proved, concludes that 

 in the corpses of persons poisoned by arsenic a similar change takes 

 place, that in the course of years arsenic is given off as a gaseous 

 compound, and that this explains the disappearance of arsenic which 

 has been observed or conjectured by many toxicologists in the exami- 

 nation of parts of exhumed bodies. 



Stokes,* iu 1888, during an examination of wall papers, fabrics, 

 and domestic articles for arsenic, placed about 300 sq. inches (about 

 0.19 sq. m.) of arsenical musliu in a glass tube connected with a 

 smaller heated tube. Air was drawn through for six hours, and 

 passed from the hot tube into an argentic nitrate solution. No ar- 

 senic was detected in the hot tube or iu the solution. The large tube 

 was then heated to 38° and air passed through the system for six 

 hours more, but with the same result. This experiment would only 

 determine whether the arsenical color was itself volatilized, but the 

 duration is so short and the test for arsenic so indefinite that the 

 experiment is of little or no value. 



My friend Professor Kinnicutt, of Worcester, Mass., has very 

 kindly allowed me to include here some experiments which he con- 

 ducted about six years ago but has never published. 



1. A room 18 by 20 feet was selected, with a wall paper contain- 

 ing 0.1 grain of arsenic per sq. yd. (7 8 mgr. per sq. m.). The win- 

 dows and door were closed, and the air of the room was drawn at the 

 rate of about 120 bubbles per minute through a chloride of calcium tube 

 filled with cotton wool and then through 5<% argentic nitrate solution. 

 After seven days neither the cotton nor the silver solution contained 

 any arsenic. The latter had a slight black deposit. The method of 

 analysis was essentially the same as in my first series of experiments. 



2. A number of pieces of cardboard were covered, by means of 



* Chem. News, LVIII. 190. 



