ACHIEVEMENTS OF CitEMICAL INDUSTRY — DUISBEEG. 255 



pletely into the complex rubber molecule on a teclinieal scale. Some- 

 what later Harries invented independently another method of aniv- 

 ing at the same result. Eveiyone is now in a position to repeat this 

 exceeduigiy simple experiment Imnsclf, but in order to confii'm Ilof- 

 mann's results, it is neccssaiy to employ pure isoprene. 



The practical value of tliis rubber^ of which many samples are 

 among the exhibits, has been tested by the liigliest authorities in 

 this branch of the industry, whilst Prof. Karl Harries, ^\•hose uiu-e- 

 mitting labors extendmg over many years, j^repared the soil for 

 Hofmann's synthesis, has carefully examined the chemical constitu- 

 tion of the substance. 



Isoprene belongs to the butadienes. It was thei-efore to be 

 assumed at the start that betamethylbutadiene would not hold a 

 peculiar and isolated position amongst the butadienes in genei-al. 

 It was argued that other members of this interesting group of hydro- 

 carbons would yield analogous and homologous rubbei-s on being 

 heated. In the synthesis of products occurrmg in nature, there is 

 always a possibility of producing such variations, and our endeavors 

 to fiiid out whether this was true in the case of rubber were crowned 

 with success, for to-day several representatives of the new class of 

 caoiitchoucs possessing different properties are known and are being 

 submitted to technical tests. Exact proof of the existence of the 

 class of isomeric and homologous caoutchoucs was also fii-st presented 

 by Elberfeld. 



To you who hear this account and see these beautiful specimens, 

 the matter appeal's very simple, intelligible, and clear. In reality, 

 however, it was not so. The difficulties vv^hich have been overcome 

 were great indeed tind those which still remain to be surmounted, in 

 order to produce a substance equal to j^ara caoutchouc in quality 

 and capable of competing with cheaj^ plantation rubber costing ordy 

 2 marlvs per Idlo, are still greater. But such difficulties do not in- 

 timidate the chemist and manufacturer; on the contrary, they spur 

 them on to further efforts. The stone is rolUng, and we will see to it 

 that it reaches its destination. The end in view is this, that arti- 

 ficial rubber ma}' soon play as important a role in the markets of the 

 world as does naturjd rubber. The consumption of rubber is simply 

 enormous. Finished articles to the value of 3 milliard marks 

 ($750,000,000) are manufactured every year, and the raw material 

 from which they are made, calculated at the present market price 

 of 12 niarl^ (S3) per kilo, costs 1 milliard marks ($250,000,000). 

 Other tasks which the chemist has on hand shrink into insignificance 

 compared with this gigantic problem. The laurel WTcath will not 

 adorn the brow of the wild dreamer but that of the scientist who, 

 cool and persevering, pursues his way. The seed he sows ripens 



