Man is by far the best underwater working device we have got. But in order to make man work underwater, we have to research several problems and to develop several measures in the field of human factor engineering of underwater life support and underwater activities.
The author suggests overall planning of the study in this field and proposes itemized list of soft-and-hard-wears to be turned out by researchers and engineers of human factors.
The list is classified into six modes of activities and divided into two categories of effect of underwater environment, i. e., (1) upon human body and (2) upon human functions.
Targets of research and development are also proposed tentatively.

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Just one hundred years ago, Paul Bert (1833-1886), a French physiologist and politician, had begun his studies on high pressure physiology, and 90 years ago, his immortal work “La Pression Barométrique, Recherches de Physiologie Expérimentale” was published. However, this book is not read, unfortunately, by alstmo of the researchers in Japan, as it is very difficult for them to get this hook.
In commemoration of the 90th anniversary of the publication of this great work, the biography of Bert and the outline of this book were shortly described.
This book is consist of 3 parts for each condition, low and high pressures: hisstorical reviews, his own experiments and summary and conclusions.
Comparing with the present status of high pressure physiology and its applications, the author picked up many of his interesting descriptions, and was surprised at a high level of knowledges and experiences on high pressure physiology and its applications at its dawning.

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One of the most important purposes of wet suit is to keep the divers warm under water, so its heat insulating capacity at the depth, where divers can arrive, must be studied. The heat insulating capacities of ten kinds of wet suit materials, of commercial foam rubber sheet were measured under high pressures.
And the following results were obtained:
(1) The authors developed a new measuring apparatus to determine the thermal conductivity of foam rubber specimens under high pressures.
(2) At the depth of 10m (at the corresponding pressures), most of the commercial wet suit materials decreased their heat insulating capacities down to 1/2 and their thicknesses from 3/5 to 2/5 of the initial ones.
(3) A relationship between the heat insulating capacity and the thickness of most of the foam rubber specimens under high pressure was almost linear. The heat insulating capacity increased with the increase of the thickness of the specimens.
(4) Under the same thickness, the heat insulating capacity increased with the decrease of the radius of isolated foam cells in the materials and of the specific gravity of materials.

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A good seat can never be obtained without adequate cushioning design, however precisely its tilt or the inclination of the back rest may be indicated.
In order to investigate the relation between the cushion of seats and their preference, a feeling test study was performed, assuming 8 items of cushioning factors. The cushioning quality was demonstrated to be approximately estimated dy the softness of the seat surface, the degree of depression, the feeling of spring and the feeling of bottom-touch.
For both of soft and hard seats, the preferred ratio of the softness of the seat to that of the back rest seemed to be constant. The optimum balance between them was studied and it was concluded that a back rest of softer surface than the seat was preferable.

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The centrarized traffic control systems are being adopted for the purpose of rationalization in J. N. R.. In the viewpoint of a complex man-machine system the investigation was made about the allocation of system functions, the error checking system, the environmental interruptions and visual displays.
The results are as follows.
(1) Man's tasks are often unsuitable mainly due to the poor system design made only in the technical viewpoint.
(2) The feedback signals of human miss operations are very poor both in quickening and indicating.
(3) Operators are forced to do complicated tasks by leaving the environmental interruptions out of consideration.
(4) Visual displays must be designed in the standpoint of what information to be given to man.

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