198 



SCIENCE. 



[N. S. Vol. XXIV. No. 607. 



the boundary lines of the fields have been 

 determined. At 66°, however, the field 

 for gypsum disappears. From these data 

 there was shown the effect of leaching 

 superphosphates by water at ordinary tem- 

 peratures. 



A Simple Fat-extraction Apparatus: G. S. 



FRAPS. 



The apparatus uses a mercury joint, and 

 is simple and cheap. 



Flavoring Extracts, Natural and Artificial, 

 in Food Products: Edv^ard Gudeman. 

 (By title.) 



A Colorimetric Method for the Determina- 

 tion of Absorbed Oxygen in Water: G. 

 B, Frankforter and A. D. Wilhoit, 

 The importance attached to the amount 

 of absorbed oxygen in a sanitary analysis 

 of water led the authors to search for a 

 colorimetric method which would be in line 

 with sanitary methods in general, and 

 which would at the same time be rapid and 

 accurate. A method using cuprous am- 

 monium chloride was finally adopted. The 

 advantages of the method, however, are 

 largely in the construction of the appa- 

 ratus. After various oils and even perfect 

 rubber stoppers were found to be inefficient 

 in protecting the colorless cuprous am- 

 monium chloride from oxidation by air, a 

 special glass stopper was devised. This 

 stopper with a siphon was fitted into the 

 top of one of the Hehner cylinders so as to 

 protect the water in the tube from the air 

 and at the same time to be used as a 

 colorimeter by making comparisons in the 

 ordinary way. The manipulation is very 

 simple. The glass cork is placed in the 

 Hehner cylinder so that the lower end 

 stands at 101 c.c. Then 100 c.c. of water 

 under examination is allowed to flow in. 

 By turning a three-way stop-cock 1 c.c. of 

 cuprous ammonium chloride is added, when 

 a blue color immediately appears depend- 

 ing in intensity upon the amount of free 



oxygen in the water. The color is matched 

 in the second Hehner cylinder by cuprie 

 ammonium chloride of known strength and 

 representing a known quantity of oxygen. 

 With this apparatus very rapid and 

 accurate determinations are possible. 

 The Estimation of Citral in Lemon Oil: 

 E. Mackay Chace. (By title.) 



ORGANIC CHEMISTRY. 



G. B. Frankforter, chairman. 



The Fruit of Smilacina racemosa and tri- 



folia: Nicholas Knight. 



The purpose of the work was, as far as 

 possible, to determine the composition of 

 the fruit. The berries were gathered be- 

 tween August 15 and September 5, 1905, 

 at Sylvan Beach, N. Y., on the shore of 

 Oneida Lake. They were allowed to ripen 

 in the house. At first they were green 

 in color and the fruit of the racemosa were 

 about the size of peas, the fruit of the 

 trifolia being smaller. As they ripened 

 both species became of a reddish color, re- 

 sembling currants. The racemosa fruit 

 contains free tartaric and a small quantity 

 of citric acid, a red coloring matter and 

 glucose. The nutlets or kernels were 

 ground and digested with boiling alcohol, 

 by which an oil or possibly two oils were 

 received. These were investigated. The 

 fruit of the trifolia showed a similar com- 

 position, the main difference being potas- 

 sium tartrate in place of the free tartaric 

 acid. 



The Constitution of Paris Green and its 



Homologues: S. Avery. 



The writer shows by a review of the 

 literature that great uncertainty exists in 

 regard to the constitution of these sub- 

 stances. Many years ago Ehrmann found 

 that a commercial sample of Paris green 

 (Schweinfurt green) consisted of three 

 molecules of copper meta-arsenite in chem- 

 ical combination with one molecule of cop- 



