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REPORT OF THE LAMP COMMITTEE

INTRODUCTION

The report of the Lamp Committee for the current year will confine itself largely to presenting statistical data with respect to the output of incandescent lamps and to other details, in the same general form as reports submitted for previous years.

During the greater part of the year the Committee has been inactive, and, except for the preparation and completion of arrangements for the lighting exhibit, has hardly more than reorganized for active work. Also the several sub-committees, which have previously been following certain details of the lamp business, can at this time only report progress.

It is felt that the incoming Lamp Committee will find a fertile field to "carry on," taking up some of the subjects which have been under investigation.

Lighting Exhibit

It will be remembered that plans had been completed in 1917 for a special lighting exhibit under the auspices of the Committee. These plans, which were interrupted in connection with all other activities of the Association because of the war, were this year revived, and the Committee presents for the attention of the delegates a general exhibit which, it is hoped, will meet with your approval and be found interesting, constructive and altogether helpful. This production which may be considered the main portion of your Committee's report, has been possible only by reason of the generosity of the lamp manufacturers and the cooperation of the Lighting Sales Bureau of the Commercial Section.*

Lamp Sales

The total sales of incandescent lamps for domestic use, excluding miniature, for the year 1918 amounted to 186,000,000 lamps, an increase of 9.4 per cent over the previous year, as compared with a gain of 17 per cent for 1917 over 1916. Of

Manuscript of this report was received April eighteenth.

*An article describing the Exhibit, together with several illustrations, was printed in the July, 1919, Bulletin, beginning on page 359.

this total, 166,000,000 lamps were of the tungsten filament type an increase of 12 per cent. There were 20,000,000 carbon filament lamps produced, including carbon and gem, a decrease of 9.5 per cent over the preceding year.

It will be seen that the tungsten lamp production represented 89 per cent of the total number of lamps sold in 1918, compared with 87 per cent for the preceding year.

Table 1 shows the distribution of lamp sales which is also indicated graphically in Fig. 1, covering the past twelve year period (1907-1918 inclusive).

Table 1

DOMESTIC INCANDESCENT LAMP SALES 1907-1918 INCLUSIVE Per Cent Carbon Per Cent

Per Cent

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Of the total tungsten lamps sold (166,000,000), there were 142,000,000 of the vacuum type, which was an increase over 1917 of 8.5 per cent, and 24,000,000 of the gas filled type, an increase over the previous year's production of 37 per cent.

Gem Lamp

METALLIZED FILAMENT LAMPS

In the report of your Committee of last year, it was stated that the demand for gem lamps was rapidly becoming less and less, and that this decrease was making it increasingly difficult to supply the lamps to fit the voltages demanded, and that the use of this type of lamp was rapidly being discontinued by central station companies.

Since that time demand for gem lamps has ceased, and about the first of this year the manufacturers discontinued entirely their production so that no gem lamps are now available.

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Thus disappears from the field this metallized filament or gem type of lamp, which first came into use in 1905 and which constituted a useful transition from the sturdy, reliable, though now considered inefficient, carbon lamp, to the modern tungsten lamp of high efficiency and great intrinsic brilliancy.

Carbon Lamp

The demand for carbon lamps (excluding gem) continues about the same as for the past two or three years. Their use still appears, generally speaking, to be confined to such places where the service is so severe, due to breakage and rough handling, that the robust quality of the carbon lamp is considered of more value than the higher efficiency of the tungsten lamp. There are, however, a few companies continuing to furnish the carbon lamp to their customers. Reference is made to this subject further on. The production of the carbon lamp has, no doubt, maintained its record for the past year, because of the

great amount of temporary lighting and of industrial construction carried on during the war period.

It is felt by your Committee that the decline of the production and use of the carbon lamp will be more rapid from now on, particularly with the possibility of the development for special uses of a more sturdy tungsten lamp, to which reference is made further on in this report.

Miniature Lamps

There has been a considerable growth in the use of tungsten miniature lamps, owing to the increased use of automobiles and flashlights, for which service these lamps are used exclusively. The number of carbon miniature lamps now used is negligible. On central station circuits, tungsten miniature lamps for candelabra and Christmas tree lighting are being used in increasing numbers.

DISTRIBUTION BY TYPES AND SIZES

The detail as to the percentages of total lamps sold in each of the various voltage groups is indicated in Table 2. More than 82 per cent of all lamps, (tungsten, carbon and gem) sold in 1918 were of the 110-125 volt group; 7.6 per cent were of the 220-250 volt group. Table 3 gives the wattage distribution for the past three years, of multiple tungsten Type B and C lamps.

Considering only tungsten lamps in the 110-125 volt group, the distribution by sizes of lamps compared with the preceding year and the percentages of increase or decrease in sales are given in Table 4. It will be seen that the 40 watt lamp is still the most popular size, more than one-quarter of the entire demand for tungsten lamps in this voltage group (110-125) being supplied in this size. The 25-watt lamp is a close second, with the 60-watt following next in order.

It will be seen that the 50 watt lamp of the vacuum class, first put on the market less than four years ago, made by far the greatest gain (30 per cent) during the year, and now occupies fourth place of the total sales of this voltage group.

The output of sign lamps shows a falling off of 33 per cent for the year, largely due, no doubt, to the curtailment in sign and other outside lighting brought about by Governmental restrictions placed upon this character of service during the war.

The 100 watt vacuum lamp is shown to have decreased considerably in sales, this lamp being displaced by the 75-150 watt gas filled lamps. The average increase in the 110-125 volt vacuum tungsten lamp sales was 7 per cent, while the sales of the gas filled lamps in this voltage group increased nearly 50 per cent.

Of the gas filled lamps, the 100 watt is still the most popular size, with the 75 watt following closely. While lamps of this type of the voltage group given show but 13.4 per cent in numbers of lamps, the wattage output is 36 per cent, that is, over onethird of the wattage of the 110-125 volt lamps sold during the year were of the gas filled type.

Table 2

1918 Distribution by Voltages of Total Lamps Sold Voltage Group

110-125 volts...

220-250 volts..

Street Series (4.0, 5.5, 6.6 and 7.5 amperes)
Street Railway (5 in series on 525-650 volts)
30 and 60 volts (Train and Farm Lighting)
Miscellaneous

Total....

Per Cent of Total Sales

82.1%

7.6%

1.3%

3.8%

4.0%

1.2%

100.0%

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