606 EXPERIMENT STATION RECOKD. 



We see everywhere catalytic icactious produced by motion, that is, 

 by the iutroduction of some kind of force. The violent explosion of 

 potassium chlorate by sulphur is to be referred to the same cause. The 

 explosion which occurs with such violence Avhen these substances are 

 rubbed together is often explained by the heat due to the rubbing. 

 This is entirely false. Experiment has shown that a mixture of potas- 

 sium chlorate and sulphur may be heated above the melting- point of 

 sulphur even without any explosion. However, with careful heating, 

 at a temperature of 142° an explosion takes place but with no violence. 



ISTitroglycerin explodes with fearful force by a blow, but it burns 

 without harm on glowing coals. It is not the heat from the rubbing or 

 from the blow which is the cause of the explosion. Before this can take 

 place the atoms of the molecules must be set in motion bj^ a mechanical 

 force, and it is this which produces the violent disruption. 



Of the greatest interest also are the discoveries of Abel ' and Cham- 

 pion and Pellet^ on the transmission of the explosive force in explosives. 

 If a little iodid of nitrogen is placed in one end of a glass tube 2.4 meters 

 long and exploded the explosive force is transmitted to iodid of nitro- 

 gen in the other end of the tube. There cau be no question of heat 

 here. It can only be the atomic vibration caused by the first explosion 

 which produces the explosion in the other end of the tube. 



Vibrations of a definite character are necessary to produce an 

 explosion. Iodid of nitrogen, when placed on the bass string of any 

 stringed instrument, will not explode if a bow is drawn across the 

 strings; but on the higher strings it will ex])lode immediately. The 

 explosion of one explosive body does not produce an explosion in a 

 second unless the vibrations of the second are synchronous with those 

 of the first. 



Just as here the exciting cause is the motion which is given off by 

 one body and which sets the atoms of a second body to vibrating so 

 violently that they are torn apart, so is it also in the case of ferments 

 and fermentable substances, or of nitrous acid and oleic acid, or of 

 fibrin or silver oxid and hydrogen peroxid, or in the case of dilute acid 

 and sugar, starch, and cellulose, etc. From each of these bodies vibra- 

 tions must be produced of a definite wave length in order to cause a 

 breaking up. of the unstable molecule of the compound which is acted 

 upon. 



Berzelius considers the formation of ether from alcohol and sulphuric 

 acid to be a catalytic reaction also. As soon as the various steps in 

 the production of ether were understood this sort of catalytic reaction 

 was no longer believed in. But it is going too far to deny it because 

 many other processes are explained on purely chemical grounds. 



Dilute acids split sugar up into glucose and fructose; dilute sul- 

 phuric acid changes cellulose and starch also into glucose. Since cellu- 



1 Compt. Rend., 69, p. 105; 78, pp. 1227, 1301, 1362, 1432. 

 * Couipt. Reud., 75, p. 210. 



