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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 = '4') AND (category.subclass = '237') ORDER BY date ASC, patent, type

Total of 1 patents found where: Class is '4'; Subclass is '237';

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T / S Patent Date Description Patentee Category Assigned To
 1897
U 589,256 August 31, 1897 Process of Making Insulating Material
Composition insulator made of paper pulp saturated with sulfur		 GRAY, John
CASE, Charles H.
 Composition  

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