Registering thermometer

1937. Six's registering thermometer (fig. 527.) is so contrived as to indicate the extreme points to which it falls or rises in the course of the day or night, and is, therefore, particularly useful as a check upon the working gardeners, who have to attend to the fires, or steam, &c., of hothouses in the winter time. In the open air it is also a very useful instrument, from its pointing out the extremes of temperature. (Nich. Encyc., art. Thermometer.)