Hayward Brothers & Eckstein Catalogue · Page 3

HAYWARD'S LENS TEST

Abstract of Summary of the Report of Professors ISAAC SYDNEY SCARF, F.I.C., Head of the Chemistry and Physics Department, and CHARLES ALFRED WEST, A.R.C.S, F.I.C., Lecturer on Experimental Physics, of The City of London College.

"All lenses were tested under exactly the same conditions, and may be compared as under:— More particularly as to Hayward's Patent No. 18P "Pludelux" Lens in comparison with that of another maker, with result as shown in diagram.

Lens Test: No. 18P, Hayward's Patent "Pludelux" Lens

The maximum angle of intensity in HAYWARD'S Patent "PLUDELUX" Lens is 16½° below the horizontal.

The maximum angle of intensity in the above Lens A is 1° below the horizontal.

HAYWARD'S PATENT "PLUDELUX" LENS is therefore the most suitable for the illumination of long rooms when the Lens is at or below the ceiling.

The proportion of light directed into basement is (see diagram)—

Hayward's Patent "Pludelux Lens		Lens A
53% of the light is directed.	31% of the light is directed.

The remainder of the light is—

I.—Lost by reflecting at the upper surface, which is the same in all lenses of equal area

II.—Lost through the back of the Lens at 30° from the vertical—

Hayward's Patent "Pludelux Lens		Lens A
5% loss.	46% loss.

The loss in Lens A is 10 times that in Hayward's Patent "Pludelux" Lens.

The experiments therefore show that, as regards the delivery of light, HAYWARD'S PATENT "PLUDELUX" LENS is much better than Lens A, and the results of the whole test further show that for equal lens apertures, Hayward's Patent "Pludelux" Lens has 68% more illuminating power than Lens A, and throws the light in a more nearly horizontal direction. (Signed) PROFESSORS SCARF AND WEST."

The above extracts illustrate clearly the great increase in illuminating power of
HAYWARD'S NEW PATENT "PLUDELUX" LIGHTS,
Nos. 18 and 19 Patterns. H. B. & E. would strongly advise Engineers and Architects, and those who have dark rooms, to inspect HAYWARD'S PATENT "PLUDELUX" LIGHTS, fixed in their basements, before deciding to put in light of inferior illuminating power.
The following are a few testimonials recently received as to the efficiency of Hayward's Lights, &c.:—

LAURIE & M'CONNAL, LTD., Cambridge, say:—"We have much pleasure in stating that the 'PLUDELUX' Pavement and Stallboard Lights and Collapsible Gates, which you have recently supplied to our new premises here, are giving us to the utmost satisfaction, and are in every way a credit to you."

F. SPENCER, Esq., of Nottingham, says:—"I feel I should be greatly remiss if I did not say how delighted both the Directors of the Industrial Provident Society and myself are, as the basement, previously unused, is now used throughout the day without any artificial light whatever."

SWITZER & CO., Dublin, say:—"We have your lights in use, and have found them very satisfactory. The outside Lights are subject to very rough usage, and they rarely chip or break."