Ci^e popular Science 0mi 



AND 



BOSTON JOURNAL OF CHEMISTRY. 



Volume XXIII. 



BOSTON, NOVEMBER, 1889. 



Number i r . 



CONTENTS, ^.-a ;g;sa 



Familiar Science. — Simple Experiments in 



Capillarity 159 



An Experiment in Inertia 159 



The British Museum of Natural History . . 160 



Cuneiform Inscriptions i6i 



The Zoological Classification of Man . . . 161 



Uranium 162 



Scientific Brevities 162 



Practical Chemlstry and the Arts. — Dis- 

 tillation 163 



A New Apparatus for the Recomposition of 



Light 163 



A Home-Made Geissler's Tube 164 



The Opacity of Glass 164 



Electrical Notes 164 



Home, Farm, and Garden. — The American 



Home 165 



Bees 165 



Protection from Clothes-Moths 165 



Gleanings 166 



Culinary Recipes 166 



Horticultural Hints 166 



Editorial. — Musical Instruments .... 167 



Discovery of Flint Implements 168 



The Paris Exhibition 169 



Meteorology for September, 1889 .... 169 

 Astronomical Phenomena for November, 



1S89 170 



Questions and Answers 170 



Literary Notes 171 



Medicine and Pharmacy. — A Worthy Form 



of Charity 171 



Medical Institutes 171 



Hypnotism in Animals 171 



Instinct the Guide to Diet 172 



Monthly Summary of Medical Progress . . 173 



Medical Memoranda 174 



Publishers' Column 174 



FaiQiliar Science. 



SIMPLE EXPERIMENTS IN 

 CAPILLARITY. 

 Capillary attraction, or that force which 

 causes litjuids to rise in minute tubes, is a 

 most interesting and important phenomenon, 

 and is governed by very complex and intricate 

 laws. There are, however, many very pretty 

 experiments to illustrate the force, which may 

 be performed by any one, and are described 

 by a contributor to Aa Nature. 



Take a piece of paper about three inches 

 long and one and a half inches wide, and 

 bend it in the centre so that the two sides 

 will form an angle of aboUt 45°. Place one 

 side carefully upon the surface of water. 

 (Fig. I.) At first the upper part will move 

 towards the moistened one, (Fig. 2), but it 



soon changes its direction and moves back- 

 wards until it is extended upon the water. 

 (Fig. 3. ) Almost any kind of paper will answer 

 for this and the following experiments, but 

 thin blotting paper is the most satisfactory 

 and rapid in action. A little boat bent up 

 out of paper, when placed upon the water 

 will, in the same manner, gradually unfold 

 and assume its former shape. 



These peculiar movements of moistened 

 paper are due to the force of capillary attrac- 

 tion, which draws the water into the minute 

 interstices between the fibres of the paper, 

 with such force that the paper tends to 

 assume its original shape. Variations of this 

 experiment are shown in Figs. 6 to 9. A 

 triangle of paper (6) is cut and folded up as 

 in 7. When placed in water, it opens auto- 

 matically, the gradual unfolding of the suc- 

 cessive plaits giving a very curious effect. 

 In 8 and 9 a star and hand are shown, which 

 are folded up as indicated by the dotted lines, 

 and the shaded part placed upon the water. 



This principle has been known to the Japa- 

 nese for many years, and among the curious 

 things sent to us from that strange land are 

 little splinters of wood, which, when placed 

 in water, unroll themselves into the numerous 

 %ures of dragons, fishes, men, etc., with 

 which Japanese art has made us all familiar. 



Wood and straw likewise show very inter- 

 esting phenomena, due to their capillary 

 nature. Take a match, and, with the aid of 

 a sharp-pointed knife, attach some little 

 splinters of wood to it, pointing downwards, 

 (Fig. 10.) On dipping tlic match into water 

 until thoroughly moistened, the splinters will 

 move in an upward direction until they take 

 the position shown in Fig. 11. 



Take a small straw, and attach to the ends 

 two little pieces of cork. Bend it in the 

 centre so that it resembles Fig. 12. Float it 

 carefully on water so that it stands upright. 

 Then moisten the angle of the bent straw 

 thoroughly, and in a short time it will 

 straighten itself out into its original shape, as 

 in Fig. 13. Figs. 14 to 17 illustrate varia- 

 tions of this experiment. A straw is bent 

 around a pencil into a spiral (14), and 

 straightens itself on being moistened ; or, 

 twisted on itself, as in 15 and 16, it untwists 

 with considerable force upon the application 

 of water. A straw may even be bent up as In 

 17, and the capillary force will be sufficient 

 to straighten it. Spears of hay are very suit- 

 able for these experiments, but sufficient time 

 must be allowed for them to thoroughly 

 absorb the moisture. 



u 



15MF 



In the vegetable world, this principle is 

 evidently of the highest importance. It ex- 

 plains the rigidity of the delicate leaves, 

 petals, tendrils, and branches of many plants, 

 and may, possibly, play a part in the move- 

 ments of climbing ones. The alternate 

 moistening and drying of the hairs or bristles 

 with which certain seeds are provided, causes 

 movements which aid them greatly in sowing 

 themselves in the ground. In fact, the prin- 

 ciple of capillary attraction is almost universal, 

 and the more it is studied, the more one is 

 impressed with the remarkable nature of its 

 phenomena, and the important part they play 

 in the great system of Nature. 



AN EXPERIMENT IN INERTIA. 



Make a little ring of thin cardboard, and 

 balance it on the mouth of a bottle, as shown 

 in the engraving. Place a small coin — a ten- 

 cent piece, for instance — on the top of the 

 ring, and try to make it fall into the bottle 

 by giving the cardboard a sudden blow. 

 Most persons will strike the outside of the 

 ring, and thus fail in the experiment, as the 

 elasticity of the cardboard will throw the 

 coin to cjuite a distance ; but, if the inside of 



