210 ANNUAL OF SCIENTIFIC DISCOVERY. 



other articles have increased, yet in no other articles, except cotton 

 and sugar, has there been any thing approaching such augmentation. 

 It is also worthy of remark that one ton of soda ash goes as far as 

 eight tons of kelp and three tons of barilla; therefore, taking the 

 charge now made for a ton of barilla and a ton of kelp, compared 

 with that of soda, a saving has been effected equivalent to 1,500,000; 

 and taking the prices of these articles, previous to the introduction of 

 soda, upwards of 5,000,000 has been saved to England. There is 

 another point in which this subject is of the highest importance. The 

 great importation of palm oil from the Western Coast of Africa shows 

 the benefit of this manufacture. Slavery, which can never stand in the 

 presence of commerce, must be thereby considerably checked. The 

 alkali manufacture is thus indirectly the minister of civilization, for by 

 establishing a system of regulated industry among the African na- 

 tions, it makes local labor valuable." 



NEW PROCESS FOR THE MANUFACTURE OF ALKALIES. 



MR. TILGHMAN, an ingenious American gentleman residing in Eng- 

 land, discovered and patented, in 1847, a method of decomposing 

 the alkaline salts by means of steam at high temperatures, and of pro- 

 ducing salts of potassa from felspar. The invention consists in de- 

 composing the sulphates and chlorides of the alkalies and alkaline 

 earths, by exposing them at a high temperature to a current of steam, 

 by which the acid is carried off, and the alkaline base either remains 

 free, or enters into combination with some third substance provided 

 for that purpose. The acid vapors passing off are condensed to form 

 sulphuric and hydrochloric acids. To obtain potassa from felspar, 

 the inventor heats together a potash felspar, with carbonate of lime, 

 and the sulphate of lime, baryta, or strontia; the mixture is after- 

 wards lixiviated with water. It is estimated that these discoveries 

 will effect a saving of nearly one half the expense in the manufacture 

 of soda and potash. The apparatus and the methods of Mr. Tilgh- 

 man have recently been introduced into the immense soda manufac- 

 tories of Mr. Tennants, at Glasgow, Scotland, and have thus far prov- 

 ed to be superior to any of the former processes. In 1848, sulphuric 

 acid, valued at more than $5,000,000, was manufactured in Great 

 Britain, and when it is considered that Mr. Tilghman is able by his 

 process to manufacture this also at a cheaper rate, the importance of 

 the discovery becomes considerably enhanced. 



NEW MODE OF MANUFACTURING SULPHATE OF SODA. 



WE learn from the Comptes Rendus for Feb. 5th, that Messrs. 

 Thomas, Dellisse, and Boucard have presented to the Academy the 

 description of a new process for converting culinary salt into sulphate 

 of soda by means of the sulphate of iron. This would allow the pyr- 

 ites to be turned to very good account. The dry and pure sulphate of 

 soda would not cost more than 2 francs the 100 kilograms,* instead 

 of 12 to 18 francs, which is the ordinary price. The new process 



* A kilogram equals 21b. 3 oz. Avoirdupois. 



