...invariable unit in this method is the light produced by the burning of a candle ; which is defined as a sperm candle of six to the pound burning at the rate of 120 grains per minute. It will be evident, upon a little reflection, that this plan is liable to serious errors in...

...sperm was just one-seventh greater than that of wax. At present, the standard flame in this country is a sperm candle of six to the pound, burning at the rate of 120 grains per hour. But for some time past this standard lus also become uncertain — first, because there has been great...

...ordinary process of photometry the standard used is a candle, defined by Act of Parliament, as a»" sperm of six to the pound, burning at the rate of 120 grains per hour." This, however, is found to be very variable, and many observers have altogether condemned the employment...

...In England, since the year 1852, the parliamentary standard of comparison has been a sperm caudle, of six to the pound, burning at the rate of 120 grains per hour. As the result of an elaborate series of experiments conducted by Professors Graham, Brande, JT Cooper,...

...just oneBcventh greater than that of wax. At present, the standard flame in this country is a sperm of six to the pound, burning at the rate of 120 grains per hour. But for some time past this standard has also become uncertain — first, because there has been great...

...satisfactory one, is the illuminating power of the standard candle. Standard candles are sperm candles, six to the pound, burning at the rate of 120 grains per hour. Other sources of light such as a gas flame are compared with one or more such LIGHT. [CH. I standard...