176 ANNUAL OF SCIENTIFIC DISCOVERY. 



gether give 9. The cube of 21 is 9,261, and that of 12 is 1,728; 

 their difference is 7,533, also a multiple of 9. 



The number 87 has also somewhat remarkable properties; 

 when multiplied by 3 or a multiple of 3 up to 27, it gives in the 

 product 3 dig-its exactly similar. From the knowledge of this the 

 multiplication of 37 is greatly facilitated, the method to be adopted 

 being to multiply merely the first cipher of the multiplicand by 

 the first multiplier; it is then unnecessary to proceed with the 

 multiplication, it being sufficient to write twice to the right hand 

 the cipher obtained, so that the same digits will stand in the unit, 

 tens, and hundreds places. 



For instance, take the results of the following table : 



37 multiplied by 3 gives 111, and 3 times 1 equals 3 



37 " 6 " 222, "3 " 2 " 6 



37 " 9 " 333, "3 " 3 " 9 



37 " 12 " 444, "3 "4 " 12 



37 " 15 " 555, "3 "5 " 15 



37 " 18 " 666, "3 "6 " 18 



37 " 21 " 777, "3 "7 21 



37 " 24 " 888, "3 "8 " 24 



37 " 27 " 999, "3 "9 " 27 



Curious Myths of the Middle Ages. 

 FACTS ABOUT WATER. 



The extent to which water mingles with bodies, apparently the 

 most solid, is very wonderful. The glittering opal is only flint 

 and water. Of every 1,200 tons of earth which a landlord has in 

 his estate, 400 are water. The snow-capped summits of Snowdon 

 and Ben Nevis have many million tons of water in a solidified 

 form. In every plaster of Paris statue, which an Italian carries 

 through our streets for sale, there is 1 pound of water to 4 pounds 

 of chalk. The air we breathe contains 5 grains of water to each 

 cubic foot of its bulk. Potatoes and turnips have, in their raw 

 state, the one 75 per cent, and the other 90 per cent, of water. 

 If a man, weighing 140 pounds, were squeezed in a hydraulic 

 press, 70 pounds of water would run out, and only 35 of dry resi- 

 due remain. A man is, chemically speaking, 45 pounds of car- 

 bon and nitrogen, diffused through 5<| pailfuls of water. In plants 

 we find water thus mingling no less wonderfully. A sun-flower 

 evaporates 1J pints of water a day, and a cabbage about the same 

 quantity. A wheat-plant exhales, in 175 days, about 100,000 

 grains of water. An acre of growing wheat, on this calculation, 

 draws and passes out about 10 tons of water per day. The sap 

 of plants is the medium through which this mass of fluid is con- 

 veyed. It forms a delicate pump, up which the watery particles 

 run with the rapidity of a swift stream. By the action of the 

 sap various properties may be accumulated to the growing plant. 

 Timber in France is, for instance, dyed by various colors mixed 

 with water, and sprinkled over the roots of the tree. Dahlias are 

 also colored by a similar process. 



