€|)c popular ^cimcc iSttus 



AND 



BOSTON JOURNAL OF CHEMISTRY. 



Volume XXIII. 



BOSTON, JANUARY, 1889. 



NCMBEK I. 



CONTENTS. 



Familiar Scienck. — Scientific Recreations . . i 



A Gigantic Fossil Tortoise I 



Sea-Water and Sea-Water Ice. 2 



Kxperimental Proof of the Existence of the 



Ether - .... 3 



Tile International (jeolotjical Con<;res* . . 3 



The Hrownian Movement 4 



Scientific Brevities ^ 



up in a conical form so that the lines a and b 

 .shall be in contact. Then look steadily at 



tirely down throuufh the chain and hang freely 

 at the bottom. This, of course, is impossible, 



Practiiai. Ciiemistrv AM) riiK .Vkis. — 



Siiifar Refining 5; 



Siilphnr 6 



Practical Recipes 6 



lIoMK. Farm and (Jardk.n.— Maize .... 7 



The Kitchen (iarclen 7 ' 



Coffee .Making S 



(fleanings 8 



ICditohial. — The Mvsterics of Cheniistiv . . 9 



The Protective Miniicrv of Insects .... 10 

 Meteorologv for November . . . . ' . . .11 

 Astronomical Phenomena for Janiiarv . . .11 



C4iiestions and .\nsvvers 12 



I.iterarv Notes 12 



Meukim; a-\I) PiiARMAtv. — Poisons .... 15 

 Peculiar Relations of Medical Men to the 



Public 13 



The Doctor at Home 14 



The School Age and School Hours .... 14 



The Phvsiological \'aUie of (^lantivalence . 15 

 Month I V Summarv of Medicil Progress . .15 



Medical Memoranda 16 



Humors 16 



the point of the cone and the apparently as it is connected with the ring B, but the 

 shapeless drawing will be transformed into a 

 portrait of M. Chkvrei'L, (Fig. 2,) the emi- 

 nent and yenerable F"rench chemist, now in 

 his one Innulred and third year. The portrait 

 will be seen with greater ease if one eye is 

 kept clo.sed at first. 



PlHI.lsHKRS Col IMS 



16 



Pan^iliar S(;ie»c«. 



SCIENTIFIC RECREATIONS. 



Some of oiu' readers nia\ lia\e seen the dis- 

 torted drawings which only show their proper 

 proportions when reflected in cvlindrical or 



conical mirrors. The accompanying illustra- 

 tion (Fig. I ) does not require any mirror to 

 yiew it in, but it is only necessary to roll it 



'I'his and similar portraits do not rec|iiire 

 any especial geometrical knowledge to pro- 

 duce, but are simply made bv rolling up a 

 piece of paper into the conical form oyer a 

 jiiece of wood cut to the proper shape, hold- 

 ing it before the eye in the proper ])osition, 

 and drawing the portrait or design directly 

 upon it. The lines will be ])roperl\- distorted 

 in the process of drawing witiioiit any care on 

 the part of the artist, and any one possessing 

 the necessar\ skill for drawing an ordinary 

 portrait can, with a little practice, produce 

 distorted ones e(|uallv as good as the example 

 giyen above. 



The magic chain (Fig. 3) is a French toy and 

 depends upon an optical illusion. Fig. 2 shows 

 the construction of the chain, which may be 

 of any con\enient length, and Fig. 1, the way 

 it is held in performing the e.xperiment. The 

 free ring, A, is held in one hand, and one of 

 tiie rings, B, in the other. If the ring A is 

 then dropped or thrown downwards with a 

 quick moyement, it will appear to drop en- 



I-'if;. ,i. 

 ap])arent niox emeiit is due to the succcssiye 

 backward and forward moyement of each 

 separate ring in tiie chain successively, which 

 takes place so c[iiickl\ tliat the eve cannot 

 follow it, and it appears as if a single ring 

 was passing through tlie links of the chain. 

 It is in fact a true \yave motion, and is an ex- 

 cellent and simple illustration of the fact that 

 in a wave there is no actual progressiye 

 moyement of the particles themselves, but 

 only a yibratory movement, and that while 

 the motion is transmitted, the particles of the 

 medium in whicli it takes place do not change 

 their position. 



We are indebted to La Nature for the en- 

 gravings illii.strating this article. 



A GIGANTIC FOSSIL TORTOISE. 



TliK accompanying illustration from La Xa- 

 ////*<; represents an immense fossil tortoise (one- 

 twelfth the natinal size) which wasfoimd near 

 the city of Ferpigiian in the Fyrenees Moun- 

 tains. It is over four feet in length and about 

 thirteen feet in circumference, and is the lar- 

 gest specimen in existence. It was found in 

 a bed of clayey limestone belonging to the 

 pliocene age ; and, as the head and limbs had 

 b£en withdrawn into the shell, after the usual 



