248 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1958 
made efficient. Thirty percent of the light energy absorbed (cor- 
responding to 8 photons per molecule) can be stored and released at a 
later time by combustion. In agriculture only a small fraction of 
one percent of the annual solar energy is stored. There are many 
reasons for this low efliciency. The half of the solar radiation which 
is in the infrared is ineffective; the growing season lasts for only a 
third of a year and the ground is entirely covered with green leaves 
for only a part of this time; the carbon dioxide of the air is too low 
in concentration; and, most important of all, the sunlight is much too 
bright for maximum efficiency. As a result of all these handicaps 
agriculture in the temperate zones of the world ordinarily grows 
only about 2 tons of dry organic material per acre per year. 
The mass culture of algae can probably produce about ten times 
as much organic material, but a heavy capital investment is required 
for water tanks, carbon dioxide enrichment, fertilizers, cooling equip- 
ment, and harvesting machinery. Research to reduce these costs 
should be encouraged. One of the best approaches is the develop- 
ment of algae which will grow in hot water and thus eliminate the 
need for artificial cooling. 
The Bell Telephone Co.’s solar battery is one of the most hopeful 
developments in photochemistry. It was the result of fundamental 
research in solid-state physics—a field supposedly far removed from 
that of solar energy. The single crystals of silicon which form the 
battery are too expensive now, but intensive research should be en- 
couraged in an attempt to find substitutes. Perhaps very cheap 
electroplated films and vaporized films of semiconducting material 
should be explored to see if they cannot be made pure enough and 
similar enough in properties to those of a single crystal. 
CONCLUSIONS 
I would like to make two suggestions. We work in a heretofore 
neglected field with no adequate means of publication. Let’s start 
now an international “Journal of Solar Energy Research and En- 
gineering.” Science develops exponentially when its scientists can 
build on the work of others. Rapid publication of results is the life 
blood of a vigorous science. No single scientific journal is now in 
existence which is read alike by the many types of engineers and 
scientists which make up this group. Lack of a proper medium for 
publishing their research has been a deterrent to young scientists 
on the threshold of a professional career and who might go into the 
development of solar energy. 
You have heard of the Geophysical Year sponsored by the United 
Nations through ICSU which in turn appoints committees and solicits 
support from national governments. Perhaps we can have a Solar 
