252 POPULAR SCIENCE MONTHLY 



localities where there are deposits of iron pyrites) into the autoclave. 

 The sulphur dioxide gas, under pressure, penetrates the pores of 

 the wood, and uniting with the moisture there forms sulphurous acid, 

 which serves the purpose of the more expensive sulphuric acid in 

 Simonsen's process. When the autoclave is opened the excess of sul- 

 phurous acid gas is easily driven off and may be used on a fresh por- 

 tion of wood. Furthermore, as less acid is left, less lime is required 

 for the neutralization which must precede the fermentation. The 

 claim is made that 25 gallons of absolute alcohol have been made from 

 one long ton of sawdust by Classen's process. 



Numerous modifications have been suggested, tried and patented, 

 but this is not the place to enter upon a detailed account of these re- 

 finements. Perhaps the most interesting is the claim made by Gentzen 

 and Eoth in their patent that the addition of ozone, while the wood 

 is being acted upon by acids and is under pressure, materially in- 

 creases the amount of cellulose converted into dextrose, glucose and 

 fermentable sugars. 



The methods may be said to be on the verge of financial success 

 and some small change or addition may any day convert a moderately 

 profitable process into a brilliant success. Problems for physical 

 chemists abound in these processes. We need to know exactly the 

 most favorable concentration of acid, the best temperatures and pres- 

 sures to be applied and the proper length of time during which the 

 acid, heat and pressure should be allowed to act. Some work has been 

 done on these questions and more is being done. For instance, it has 

 been proved that prolonged action of the acid is harmful, for fer- 

 mentable sugars which are formed early are later destroyed. It is 

 therefore necessary to interrupt the process at the right time. Such 

 experiments cost money and the time of highly educated men, and no 

 one would dare to say positively that they would result in the discovery 

 of a bonanza. Unfortunately, our manufacturers do not yet realize 

 of what value truly scientific, highly trained, high-priced men would 

 be to them, while the German manufacturers do, and so we may ex- 

 pect these, and almost all other such experiments, to be carried out, 

 and the results to be obtained, in Germany. We shall get them after 

 they have passed through the patent office and shall, very likely, soon 

 be making large quantities of ethyl alcohol from wood, paying royalties 

 to Germans for the privilege. 



The suggestion has been made that a process for the manufacture 

 of alcohol might be run profitably in conjunction with wood-pulp paper 

 mills. There does not appear to be the least chance of utilizing the 

 waste from the end of the sulphite process because it contains little 

 or nothing fermentable. It has already been subjected for a long while 

 to the action of sulphurous acid and the fermentable sugars, pro- 



