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SELECT DISTINCT patent.*, YEAR(date) as year FROM patent LEFT JOIN category ON category.patent = patent.patent AND category.type = patent.type WHERE (category.class = '423') AND (category.subclass = '189') ORDER BY date ASC, patent, type

Total of 2 patents found where: Class is '423'; Subclass is '189';

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T / S Patent Date Description Patentee Category Assigned To
 1920
U 1,327,781 January 13, 1920 Process of Extracting Potassium from Potash-Bearing Silicate Minerals
Process of extracting potassium to be used in glass manufacture (see patent 1,312,053; 1,327,782)		 SCHOLES, Samuel R.
BRENNER, Ralph F.
 Glass  
U 1,327,782 January 13, 1920 Process of Obtaining Combined Potassium from Minerals
Process of extracting potassium to be used in glass manufacture (see patent 1,312,053; 1,327,781)		 SCHOLES, Samuel R.
 Glass  

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