The technology of rotary converters was replaced in the early 20th century by mercury-vapor rectifiers, which were smaller, did not produce vibration and noise, and required less maintenance.
सर्दियों में उसे खेत - खलिहान , वन - पर्वत , नदी - नालों आदि में श्रम तथा कृषि कार्य करना संभव नहीं होता .WikiMatrix WikiMatrix