pared with 100,000,000 for 1913, or an increase over that year of 10 per cent. Comparison is made with the year 1913 because of the abnormal conditions existing in 1914, already referred to. The following table (Table 1) shows the approximate disbatan of the lamp business by classes of lamps over a period of nine years It will be seen that during 1907 the carbon and gem lamp lexiness represented 99 per cent of the total sales, whereas the **t of the mazda lamp during the past year was but slightly ster 79 per cent, or almost four times the total sales of all other fines of lamps combined. It may therefore be said that the higher y lamps now practically dominate the field, the sale of tatum Latips having dropped to 5 43 per cent, while the productur, of the gem lamp has fallen from 31 41 to 1568 per cent durng the last two years. 1 TABLE I Approximate. Distrimi tion of Domestic Incandescent Lamp SALES 19:5 Inclusive, Showing Fach Class Carbon, Gem, Tantalum and Marda in Percentage of the Annual Total Carves similar to those shown last year are indicated in Fig rating graphically this shifting from one type of lamp to her for the period stated -nine years The sales of the 50-watt mazda B lamp will be noted as havmenced in December, 1915. The introduction of this ich will be more particularly referred to later on in the put, w. no doubt tend to greatly increase the percentage of arda lamp sales during the coming year. Tale II, which is an extension of similar figures presente l last year, shows the percentage of distribution of mazda lamps among the various sizes. The table is arranged in parallel col urns for the years 1913 1914 1915, covering the total number of tarda lamps of all types, and in separate columns for the years 1914 and 1915, comparing the percentages of each size of the rar la multiple type only. It will be noted that the largest relative gains am ng the mt; le Lamps are for the 200 and 300 watt sizes and that the 25 watt size represents but 2 per cent of the total number of arda B lamps sold during the year. In the street series lamps the sales of the sizes below 100 cat Eepower have declined, while the Type Clamp in sizes above 1-1 watt, except for the 1000 candlepower, show relative gains The more general use of the mazda lamp makes for interesting comparison in average candlepower and wattage of all lamps sold, the complete comparison from 1907 to 1915, inclusive, being as follows: It will be seen that for 1915 there was a considerable rise in candlepower with a slight fall in wattage, the average wattage for 1915 being slightly in excess of that for 1913. It is also interesting to note that the average candlepower of lamps sold during 1915 was 42.23 or nearly two and one-half times the average candlepower represented by the sales during the year 1907. Dividing this candlepower by the wattage shows the average efficiency to be approximately 0.892 candles per watt, which is an increase over 1914 of approximately 10 per cent. As the increase in average candlepower and watts for the past year (1915) is affected by the wider and more general use of the mazda C lamp, comparative figures are given which exclude consideration of the Type C lamp. These figures are as follows. Avg. cp, excluding mazda C 1914 35.3 45. 1915 35.4 42.7 Table III is presented, showing changes in mean horizontal and spherical candlepower per watt and the date of introduction |