March 3, 1911] 



SCIENCE 



347 



residue, 1 to 5 per cent, of tar, 25-35 of con- 

 densed water. The gaseous products ranged from 

 15 to 25 liters per 100 grams of coal. The gaseous 

 products were characterized by the very large 

 amount of carbon dioxide they contained. It 

 varied from 20 to 40 per cent., depending upon 

 the locality of the lignite. There was an increase 

 of hydrocarbons and a decrease of carbon dioxide 

 in the gases from the lignites passing from south 

 to north. The samples likewise resembled bitu- 

 minous coal more closely from south to north. 

 Snow as a Means of Studying the Smoke Nui- 

 sance: Geo. B. Fbankfoeter. 

 In this paper snow has been used as a means of 

 determining these constituents. After the snow 

 had covered the ground for a given time, the 

 amount on a square foot of ground was collected, 

 melted and the solid matter filtered off and 

 weighed. The solids were analyzed and finally 

 the water was examined for the soluble solids 

 and gases. 



The amount of solid matter which fell during 

 six weeks of winter weather in the cities of 

 Minneapolis and St. Paul varied from .3 to 2.69 

 grams per square foot within the city limits. 

 An average of ten analyses gave 1.43 grams per 

 square foot. Calculated on the basis of one gram 

 per square foot, there would be 43.56 kilograms 

 per acre or 27.8 tons per square mile. 



An average of ten analyses gave 57.16 per cent. 

 of carbon and 42.84 per cent, of ash. 



Average of ten analyses of the ash gave the 

 following: 



SiO, 50.50 



Ca 1.13 



Mg 0.31 



Fe 12.10 



Al 14.26 



Alkalies 1.70 



The snow water was then analyzed and found 

 to contain a considerable amount of soluble 

 matter. 



An average of ten analyses gave the following: 



Parts per 

 Million 



Total solids 39.5 



Chlorine 5.1 



Free ammonia 0.26 



Nitrites 0.038 



Organic matter (oxygen consumed) 2.49 

 SO4 4.84 



A New Indicator: Ohas. P. Fox. 

 The bark of a Congo rubber-producing vine, 



said to be one of the Landolphias, gives an aque- 

 ous extract which exhibits the properties of an 

 indicator. Alkalies give a deep red (magenta) ; 

 acids, a light yellow to colorless. Change is 

 sharp enough for use in technical work. The 

 aqueous preparation is unstable. The coloring 

 substance is precipitated by acids. 



A Quantitative Expression of the Periodic Classi- 

 fication of the Elements: Feedekick G. Jack- 

 son. 



A chart was shown on which the atomic weights 

 of the elements were plotted, the members of each 

 small period being plotted on equidistant ab- 

 scissae, and an increasing multiple of 22 being 

 subtracted from the atomic weights. The prin- 

 cipal families of the elements were shown by 

 connecting their members by lines. From these 

 lines it was graphically shown that the values at 

 present assigned to A and Te are three or four 

 units too great, aad it was suggested that Se may 

 also be too high. Other interesting relations were 

 indicated between different family lines. 



A Simple Hydrogen Sulfide Generator: J. I. D. 



Hinds, University of Nashville, Nashville, Tenn. 



The apparatus is in one piece. The acid is 

 added drop by drop to the sulfid and when the 

 stopcock in the delivery tube is closed the acid is 

 driven immediately away from the sulfid and 

 action ceases. Advantages : ( 1 ) the quantity of 

 acid in generator is always small; (2) if the 

 acid is properly added it is practically exhausted 

 when it passes out; (3) it is cheap, economical, 

 no waste of gas; (4) it empties itself whenever 

 the gas is cut off; (5) the waste flows away 

 automatically to the sink or the open air; (6) it 

 is always ready and may be carried from place to 

 place. 



Sulfite Method for Separating and Identifying 

 Strontium and Calcium: J. I. D. Hinds. 

 Principle — Barium sulfite is difBeultly soluble 



in hydrochloric acid; strontium sulfite is difli- 



cultly soluble in acetic acid; calcium sulfite is 



easily soluble in both acids. 



1. To a small portion of the solution (1 or 

 2 c.c. ) add a drop of dilute hydrochloric acid, 

 then a few drops of a concentrated solution of 

 sodium sulfite. A white precipitate is barium 

 sulfite and indicates barium. 



2. To another small portion of the solution add 

 a little dilute acetic acid and a few drops of 

 sodium sulfite solution and heat to boiling. A 

 white precipitate is barium sulfite or strontium 

 sulfite or both. In the absence of barium, it can 



