Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a man demonstrating a small movable air raid alarm . 10 March

Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a man demonstrating a small movable air raid alarm . 10 March Stock Photo

RMID:2BW3F2H

Image details

Contributor:

Smith Archive / Alamy Stock Photo

Image ID:

2BW3F2H

File size:

95.5 MB (3.7 MB Compressed download)

Releases:

Model - no | Property - noDo I need a release?

Dimensions:

6716 x 4970 px | 56.9 x 42.1 cm | 22.4 x 16.6 inches | 300dpi

Date taken:

26 May 2020

Photographer:

More information:

This image could have imperfections as it’s either historical or reportage.

Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a man demonstrating a small movable air raid alarm . 10 March 1936

Available for editorial and personal use only. Get in touch for commercial uses.

Search stock photos by tags

Similar stock images

RM2BW3F3Y–Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a vocal gas alarm being tried at at Hendon . The microphone i

RM2BW3F3B–Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a vocal gas alarm being tried at at Hendon . The microphone i

RM2BW3F3D–Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a man demonstrating a small movable air raid alarm . 10 March

RM2BW3F3C–Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a vocal gas alarm being tried at at Hendon . The microphone i

RM2BW3F2P–Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a man using a horn and a ratchet as a warning against a pract

RM2BW3F38–Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , two children blocking their ears against the din made by a cy

RM2BW3F37–Vocal gas alarm tested . Test are being made at Hendon to discover the best warnings in the event of a gas attack from the air . Sirens are being sounded separately from Hendon Police station , which is in the centre of a ring of observers , policemen the stationed in pairs at distances of 100 , 200 , 300 , 400 yards away . They have sound recording instruments to determine the power and penertration of the various notes . The findings of the observers will be recorded on a special map , and the best siren discovered . Photo shows , a vocal gas alarm being tried at at Hendon . The microphone i