340 



SCIENCE, 



[Vol, V., No. 116. 



The quantity of alkali required to saponify 

 the fat is another valuable means of judging 

 of the purity of a butter. This equivalent is 

 an abstract number obtained by dividing the 

 molecular weight of the alkali employed by 

 the number of milligrams of it used in saponi- 

 fying a given weight of the fat. Butter-fat 

 contains acids (butyric chiefly) which have a 

 lower molecular weight than oleic, margaric, 

 and palmic acids. The saturation equivalent 

 of a butter- fat is therefore expressed by a 

 smaller number than if it were composed solely 

 of glycerides of the acids with a higher molec- 

 ular weight. The determination of the equiv- 

 alent being an easy one, it is generally made 

 as the first test in determining the genuineness 

 of a butter sample. For genuine butters, this 

 number is about 245. When it goes above 

 250, the samples should be regarded with sus- 

 picion. In one case of a. Jersey butter very 

 rich in butyric acid, this number fell to 239.8. 

 On the other hand, in four samples of tallow, 

 lard, and oleomargarine (two), the numbers 

 were 280, 284, 282, and 281 respectively. 



Pure butter contains a certain proportion of 

 glycerides of fat acids soluble in water (but}'ric, 

 capronic, caprylic, etc.). The percentage of 

 these acids to the total weight of butter-fat is 

 about five. In thirty analyses the lowest 

 percentage found was 4.49, and the highest 

 (except in one case) 5.66. In the case of the 

 Jersey cow's butter, already mentioned, this 

 number was 6.79. Tallow and lard have at 

 most only a trace of these acids. In commer- 

 cial oleomargarines the highest percentage 

 found was .56, and the lowest .20. The deter- 

 mination of the soluble acid requires much 

 time ; but it is not a difficult operation, and it 

 is the most certain method of determining the 

 purity of a butter. A sample which would 

 give no more than four per cent soluble acid 

 would be open to condemnation. It would 

 either be a very poor sample of genuine butter 

 or else an adulterated article. 



Pure butter which has not been melted gives, 

 with polarized light and a selenite plate, a pure 

 uniform tint of red or blue to the field of 

 vision. Adulterated butter in similar circum- 

 stances always gives a mottled appearance to 

 the field. This is a very simple and speedy 

 qualitative test for the purity of butter, but is 

 not sufficient in itself to definitely determine 

 the matter. 



The difficulties which make the analyses of 

 milks of little practical value are equally as 

 great with butter. A more extensive study 

 of their composition, however, is certain to 

 lead to profitable results. H. W. Wiley. 



THE SASKATCHEWAN COUNTRY. 



The district at present attracting attention 

 as the scene of an insurrection of half-breeds 

 and Indians against the Canadian government 

 is situated on the North Saskatchewan River, 

 near the northern margin of the great plains. 

 The vast region of plain and prairie, which 

 occupies the whole central portion of the con- 

 tinent, crosses the 49th parallel of latitude — 

 which constitutes the international boundary- 

 line — with a width of 750 miles, but extends 

 north of the boundary about 300 miles only, 

 being there limited by the edge of the great 

 northern forest which stretches, with little in- 

 terruption, to beyond the arctic circle. Prai- 

 ries of considerable size occur, it is true, in 

 the valley of the Peace, but these are isolated 

 from the great plains by wide forests. There 

 is reason to believe that the greater part of 

 the prairie country in Canadian territory might 

 become permanently wooded but for the almost 

 annually recurring prairie-fires, which are still 

 tending to increase its area. The southern 

 edge of the forest is, however, in the main, 

 coincident with that of a region of abundant 

 rainfall. 



The northern border of the prairie country 

 may be generally defined by a line drawn from 

 the vicinity of the city of Winnipeg westward 

 to the junction of the Assiniboine and Qu'- 

 Appelle rivers ; thence north-westward to- the 

 junction of the North and South Saskatche- 

 wan rivers ; thence westward, nearly following 

 the latter river, to Edmonton ; from that point 

 south-westward to Calgary, on the Bow ; and 

 thence southward along the eastern base of 

 the Rocky Mountains. The total area thus 

 outlined, which is either altogether treeless or 

 characterized by wide stretches of prairie in- 

 terspersed with scattered groves of aspen and 

 other trees, is approximately 300,000 square 

 miles. The southern and south-western parts 

 of this region may be described as entirely 

 without wood, though even there the rivers 

 are almost invariably fringed by groves of Cot- 

 tonwood. 



The general elevation of the plains of the 

 Canadian north-west is very considerably less 

 than that of the corresponding portion of the 

 continent farther south, the mean height of the 

 whole region above outlined being probably 

 less than two thousand feet above the sea- level. 

 The most pronounced inclination, however, 

 giving direction to the rivers of this portion of 

 the great plains, is that from the base of the 

 Rocky Mountains to the east or north-east. 

 The Red-River valley, which constitutes the 



