THE CENTRAL COMMITTEE 259
possible to discover the nature of the gas used by the Germans and
to gain a fair knowledge of the symptoms and progress of the poisoning.
 The experts of the Zemstvo Union finally produced a gas
mask of a type® which was recognized by a conference of experts as
the most suitable one and was officially adopted. The production of
gas masks was started all over the country, but it was soon found
that the skill and precision required for their successful manufacture
 made it necessary to concentrate the work in Moscow. Consequently,
 a special workshop was opened under the auspices of the
Central Committee of the Union and equipped with 270 sewing machines.
 Its daily output was about 20,000 masks and the total produced
 by the Union was 4,200,000 masks supplied direct to the
army and 2,757,000 parts of masks on orders received from the Red
Cross. There were also 467,000 gas masks for horses produced at
this shop.
Although the gas masks were being constantly improved, it was
found in the autumn of 1915 that the type adopted by the Union
was not very effective except in case of chlorine gas. At the same
time, as the Allies became better acquainted with the problem of
chemical warfare, it was discovered that the Germans had a large
assortment of poison gas. This fact came to light as early as August,
1915, and the Zemstvo Union decided to organize the production of
dry gas masks. A number of experiments were carried out, to ascertain
 the most suitable design. At Petrograd, however, the new proposals
 of the Union, involving additional expenditure and the substitution
 of new masks for those already in use, were unfavorably
received, and it became therefore necessary to start a regular campaign
 in the press and by public lectures, and by causing unofficial
organizations and learned societies to make representations to the
Government.
Not until April, 1916, could the authorities at Petrograd be induced
 to accept the views of the Union. The proposed gas mask of
the Zelinsky-Kummandt type was approved by the higher military
authorities and it became possible to begin its wholesale production.
This gas mask consisted of a tin box filled with carbon prepared by
a special process and connected with a rubber face mask with eyeglasses.
 The greatest difficulty was found in producing suitable
® The so-called “wet type” of gas mask, made of gauze with attached everlasses.