64 



of a portion of sucrose into glucose, thereby diminishing the amount of sugar that 

 should be obtained. On the same page are detailed the experiments made to over- 

 come this defect. Experiment No. 4, " the addition of freshly precipitated carbonate 

 of lime to the ' extraction bottle,' " was suggested by Mr. Swensou, the superintend- 

 ent of the experiments, under the foregoing employment. Comments on the result 

 of this experiment will be found on pages 32 and 33 of Bull. 16. 



Experiments at Fort Scott, Kans., were discontinued on November 15, 1886, and 

 the service of Mr. Swenson as agent of this Department ceased on that day. 



On December 29, 1886, Mr. Swenson filed an application for letters patent for an 

 improvement in the manufacture of sugar, and on October 11, 1887, letters patent No. 

 371528 were issued to him. 



This patent is for the use of carbonate of lime and carbonates of other alkaline 

 earths in the diffusion bath to prevent the invertive action of organic acids during 

 the process of extraction. It is simply a patent for experiment No. 4, as made at 

 Fort Scott, Kans., by this Department, and set out on page 28 of Bull. 16. 



I am informed that Mr. Swensou is now threatening to prosecute all persons who 

 shall use the method described and covered by his patent, and this Department, still 

 being engaged in experimentation for the manufacture of sugar, will be liable to Mr. 

 Sweusou in damages for using a process discovered by itself, if the patent aforesaid 

 is rightfully the property of Mr. Swenson. 



II. 



CONDITION OF THE ART. 



The aforesaid patent is for the use of carbonate of the alkaline earths to neutralize 

 organic acids present in saccharine solutions, and thus prevent inversion of sucrose 

 into glucose. This is not new, and has been known to those engaged in the art of 

 manufacture of sugar for years, and allusions are to be met with to its use in works 

 describing this art, and patents have been issued for this same means for neutralizing 

 acidity in saccharine solutions in England. A brief reference to some of these will be 

 made. 



In a work entitled "Sugar Growing and Refining," by Wigner and Harland, pub- 

 lished in London in 1882,, the following allusions are made pertinent to this part of 

 the art. 



On page 185, in describing the diffusion process, it says: 



" In order to insure the solidification in the tissues of the soluble substance injuri- 

 ous to the sugar, especially of pectiue, which is not coagulated by hot water alone, 

 lime or some other suitable agent may be added to the water or liquor." 



On page 504 of the same work, in speaking of the alum process, it says : 



" After the separation of the alum it is possible to neutralize the acid liquor with 

 cltalk (carbonate of lime) only, and this has been done on a large scale for a consider- 

 able time. The use of chalk has an advantage over lime in that should an excess be 

 added it does no harm to the sirup beyond simply increasing the insoluble deposit in the 

 filters:' 



A description of the identical advantage claimed by Mr. Swenson in his patent, 

 lines 52 to 58, * * * "it is possible to neutralize the acid liquor with some other 

 alkaline body instead of lime; among other substances which have been tried for 

 this purpose are ammonia, carbonate of ammonia, baryta, carbonate of baryta, stron- 

 tia, carbonate of strontia, magnesia, carbonate of magnesia." These are the carbon- 

 ates of alkaline earths mentioned in the patent, lines 58 to 63. 



In a pamphlet published in Cincinnati in 1876, entitled " Extraction du Jus Sucre" 

 des Plantes saccharifdres, par Diffusion," the author of which is G. Bouscaren, is 

 found, on page 2, a description of the alleged improvement patented by Swenson, and 

 it speaks of the addition of chalk (carbonate of lime) to either the water of the dif- 

 fusion battery or to the pulp of the cane itself before it goes into the battery. 



