A RETIRED naval architect of New York City, I. C. G. Cooper, has developed an avocation which combines half a dozen sciences-chemistry, optics, taxonomy, histology, genetics and hydroponics. All of these activities converge on one project: growing algae.

Algae have become a popular subject with science writers, engineers and even bankers, who see these aquatic plants as a promising source of food, fuel and process chemicals. When Cooper took up his hobby 20 years ago, however, algae were just scum on ponds and a subject in botany books; few laymen thought of them as objects of beauty or commercial opportunity. It is only since World War II that laboratories and pilot plants have sprung up in various countries to explore their possibilities. As Harold W. Milner reported in his article in the October, 1953, issue of SCIENTIFIC AMERICAN (Algae as Food"), the results so far are spectacular. On the basis of the preliminary work it is estimated that we can grow 40 tons of algae per year on every acre given over to algal culture equipment. That would be the equivalent of 20 tons of scarce and valuable protein and three tons of equally scarce fat per acre- astronomical figures compared with production rates in agriculture.

But it will be a long time before algae products appear at your corner grocery store. There are big problems to solve, and of the 10,000 species of algae that are candidates for culture, fewer than 30 have been studied in detail.

The algae range in size from microscopic single cells to kelps nearly as tall as an oak tree. Some algal species live in boiling natural springs; others thrive in the polar wastes. The algae have adopted almost every method of reproduction known to biologists. If variety is what you want in a hobby, the algae should satisfy you.

Cooper has a considerable collection of algae, but his interest is not in collecting but in culturing these organisms. He writes:

"The algae have given me an excuse for playing with a whole basement full of scientific gadgetry, which includes everything from microbalances and microscopes to geologists' picks. I have had a lot of fun with these plants, and you can imagine how stimulating it has been to see them come in for major recognition during the past few years. I must confess that when I got into this thing I had no intention of taking up a hobby, much less of tangling with a group of sciences in which I had no background. I merely started out one afternoon for a pleasant walk in the woods.

"William T. Davis, an amateur naturalist and one of the founders of the Staten Island Institute of Arts and Sciences, had volunteered to teach me how to identify some of our local wildflowers. His enthusiasm was contagious, and before the afternoon was over the bug had bitten me.

"During the next few months I gathered and mounted a lot of flowers and weeds. Before long it became evident that I was a little late with my discoveries; the specimens I collected were already represented in the Institute's display cases. It seemed pointless to go on duplicating work already well done. Then one evening at the end of a field trip I took a short-cut home by way of the beach and noticed a strange clump of seaweed waving back and forth in the low tide. I took off my shoes and waded in. After I had pulled up a specimen of the plant, I had an idea: Why not make a study of Staten Island's marine flora?

"Although that first specimen turned out to be only a common variety of rockweed, it occupies a special place in my collection because it introduced me to the thallophytes, the grand division of the plant kingdom occupied by the algae.

"You don't need a scientist's background to get fun out of collecting algae, especially the big ones. You simply float them in whole or in part onto a sheet of paper and let them dry. The leaflike parts of many consist of only two layers of cells coated with a clear pectinous substance. They dry on the paper without apparent thickness, like ink, and few artists paint more colorful or exotic abstractions.

"Things went along nicely for a couple of years, and my original rockweed grew into quite a substantial collection. Then the job became rough. As I worked my way down the scale of algal sizes, the number of species increased all out of proportion. Identification became difficult. The reference texts, which fully describe the giant kelps and often carry colored illustrations of them, become sketchy when you get down to the species that make a pocket magnifier handy.

"Without knowing it would make matters worse, I bought a microscope. The first look through it almost ended my new hobby. Here was no man's land. I could not even distinguish between plants and animals, much less identify the plants. A single drop of fluid scraped from a stalk of marsh grass would hold scores of organisms, including animals that grow in branching patterns like plants and plants that swim by means of whiplike tails and eat like animals! At this point I want to put in a good word for the patience of our museum's curators and that of my fellow members in the New York Microscopical Society. They finally succeeded in teaching me how to recognize a chloroplast when I saw one, and also to identify the cellulose walls which aid in distinguishing one biological kingdom from the other.

"But learning how to tell plants from animals was only a beginning. Each drop of liquid that appears under the microscope's objective contains a unique population. Before I could complete a census, the drop would evaporate and destroy the individuals. How do you introduce order into a scramble like this, and where do you begin?

"It is a good idea, the curators advised, to commence by narrowing your field. Staten Island is not large as islands go, but in terms of its algal population it is vast. In naively undertaking the collection of all our local 'seaweed' I had staked out too much territory. After years of sampling the immensely various populations of algae in the island's waters, I decided I would have to limit myself to the less abundant algae of the soil

"As a rule, algae are not too difficult to find in the soil once you have picked up a bit of experience in handling cultures and the microscope. But separating them into individual species and exploring their structure and behavior can get you embroiled in all sorts of puzzles and complications. Fortunately the phycologists and bacteriologists have solved the hard problems of method, and it is not difficult to adapt their techniques to an amateur's studies.

"I use the so-called 'soil-water' culture method advocated by E. G. Pringsheim of Cambridge University. In effect the algae grow in a miniature artificial pond -a glass jar of nutrient solution covering a bottom of mud [see drawings at right]. The pond is prepared by partly filling a wide-mouthed glass container- such as a peanut-butter jar-with nutrient solution, adding a tablespoonful of soil and then sterilizing the whole in an autoclave. The pond is then inoculated with the specimen of soil to be investigated. A pinch does the job. The pond is kept at room temperature and exposed to light during incubation; a window having a northern exposure is a good light source.

"After incubation is completed-when the characteristic green 'scum' appears in quantity-a smear of the culture is transferred to an agar plate where it continues to grow. If the smear has been made carefully, distinct colonies of the various organisms will appear here and there on the plate. You then pick out one of these with a glass needle or a micropipette and inoculate a second sterile pond with it. What you thought was a colony of identical organisms will likely prove to be a mixture-but the second pond will be less motley than the first. You continue this cycle of operations until your species appear in splendid isolation-or your patience gives out. Sometimes I wonder if it is possible to develop a perfectly pure culture of anything.

"Single-celled algae are enveloped by the same pectinous substance that causes the giant kelps to dry on paper so beautifully. This sheath is usually alive with bacteria. Just try to kill them without killing the algae! Irradiation by X-ray or ultraviolet light in measured doses tends to kill the bacteria without destroying all the algae. But even if you succeed in knocking out the bacteria without damaging the plant, you still face the job of separating the alga from the culture without contaminating it and of inducing it to grow in a fresh pond. I have not tackled that experiment so far. Problems like this can tempt you into getting mixed up with X-ray machines and lots of other costly gadgetry.

"Keeping things simple and resisting the urge to follow every byway that opens is the most difficult part of my hobby. This year my resistance broke down again, and I am now constructing a reflecting spectroscope, as described in Amateur Telescope Making-Book III. It requires time which should perhaps be devoted to the cultures. But I reconcile this cost by telling myself that I have learned a little about replica gratings and that a mighty useful gadget will soon be on hand. You come up against a lot of chemical problems in the course of growing algae, such as the analysis of nutrient solutions for their content of minor elements. My limited chemical facilities were not up to such exacting work and so I sold myself on the necessity of taking time out for constructing the spectroscope and learning how to use it for chemical analysis.

"The artificial-pond technique always leaves you with a number of chemical unknowns. I hope the spectroscope will eliminate some of them. The growing culture takes part of its nourishment from elements added to the solution and part from sterilized soil. The first are under your control. If we could grow cultures by pure hydroponic methods, a lot of question marks that come with the soil would vanish. But that would necessitate a comprehensive knowledge of the organism's nutrient requirements in advance of growing a culture of it. Hence we combine the major elements-nitrogen, potassium, magnesium and others common to all plants-in the nutrient solution and rely on the 'mud' phase to supply the minor ones plus other unknown factors such as vitamins. The mud also serves as a reservoir and a place of reduction and synthesis for keeping the heavy metals in solution. Incidentally, the proper soil for the pond's bottom must be found by trial. After a lot of sampling, I located one that works unusually well. A large quantity of it was sterilized at one time by autoclaving and stored in sealed containers for future use.

"Friends sometimes ask what I do with an alga when it has been isolated and added to the collection of cultures. In a way that is like asking a philatelist what he does with his stamps. If he is a good philatelist, he preserves them carefully and tries to learn something from them. Preserving live algae is no less satisfying nor more difficult than caring for any other plant. If you give them light, water and food, and maintain the temperature they prefer, they glow with health. In turn they challenge you to discover how they react to such things as subtle changes in diet; how, when and by means of what mechanism they reproduce; what products their metabolism yields-and the countless related secrets of their life processes. In accepting this challenge you can, as they say, dive in as deeply and stay down as long as you wish. I have been at it now for some years without getting more than my feet wet.

"Those who enjoy hydroponics like to develop nutrients, and I have had some success in this work. One series of experiments ended in a solution which seems to work better for me than those listed in the reference texts. You lay out a set of slightly differing ponds in a rectangular grid, with a single element in the nutrient progressively diluted more and more in each vertical row. The entire grid is inoculated and kept under observation. A detailed record of the culture's reaction in each pond is made. The experiment can be continued by simultaneously altering the strength of two elements in each vertical row, then three elements and so on. An analysis of the accumulated record discloses the ideal concentration of each element in the nutrient for the species under study. Incidentally, a culture subjected to this study becomes a tool of great power and subtlety for investigating unknown nutrients. The alga's reactions when transferred to the unknown nutrient provide an indication of the ingredients present and, in some cases, a quantitative measure of their concentrations.

"Once a culture has been standardized, that is to say, brought to a reasonable state of purity and provided with the preferred nutrient, it suggests endless other experiments. If the alga employs sexual reproduction, for example, you can attempt to mate it with a near relative and create a hybrid. It is interesting to modify a plant's diet and observe the result. A heavy concentration of nitrogen can cause Chlorella, an alga which may become commercially important, to increase its production of protein from about half its weight to almost 90 per cent. In contrast, putting Chlorella on a starvation diet of nitrogen boosts fat production from something under 10 per cent to more than 70 per cent. The commercial implications are obvious.

"It is easy to see how such metabolic gymnastics can fascinate the amateur. Learning to observe such changes, to take the plants apart and measure the substances of their bodies, or those that appear as by-products, will bring you into contact with as many fields of science as you have time and talent to enjoy."

AN IDEAL approach to becoming an advanced amateur astronomer is to begin by building a 6-inch reflector, use it a season, and then progress to 8-inch, to 10-inch and (if that does not satisfy) to 12-1/2 inch telescopes-the sizes are based upon available Pyrex mirror disks. This sounds like a long lot of hard work. But to start with the ultimate size robs the builder of the fun of designing and making the series of mirrors and becoming an expert in the process. After building several telescopes an amateur has a right to regard himself as advanced and seasoned.

This account is about two amateurs who began with a 12-1/2 inch telescope be cause they had inherited a 12-1/2 inch mirror completed by a friend who had died. Robert and Karl Esch of Cherryvale, Kan., and their neighbors put "uncounted hours" on the project (see this department for May, 1952), but when they put the big telescope to use, the stars danced in the eyepiece. They had used solid steel axis shafts 178 inches in diameter, but evidently these were not massive enough. After inspecting a professionally built instrument at the University of Kansas and noting its massive solidity, Robert went home and wholly redesigned and rebuilt the mounting. Roger Hayward's drawing on page 110 shows its new proportions, Karl says: "This one really has rigidity. I had little to do with the mounting, which was designed and built by my brother Bob, though I made a new 12-1/2 inch mirror for it and was responsible for the rest of the optical parts."

What the brothers had overlooked in their first mounting was the fact that a telescope magnifies tiny vibrations in proportion to its own magnification and must therefore be much more rugged than other machines.

Robert's new design was inspired by illustrations in the Amateur Telescope Making books of Russell W. Porter's stocky mountings for a 12-inch reflector and for the 18-inch Schmidt at the Palomar Observatory. Robert says: "The result of all our efforts in fattening the axes was more than fruitful."

It has sometimes been urged that the data of engineering stress analysis be furnished for guidance in the design of telescope mountings. Such instructions were published in this department in April, 1951, but they have had no observable effect beyond the fact that a number of readers quarreled with them because they called for mountings that seemed unnecessarily rugged. Axes 6-7/16 inches in diameter for a 12-1/2 inch telescope were "big beyond reason." One who quarreled with them was Karl Esch, then an engineering student. Nevertheless, older brother Bob made the new housings eight inches in diameter.

I have an inch-thick file of round-robin correspondence on this matter with advanced amateurs. Some of the readers quarreled with each other. From the protracted argument the main facts that emerge are that the sizes of telescope parts are highly dependent upon the assumptions made at the beginning, and that these assumptions vary, are arbitrary and have only an uncertain basis in optics. A dozen readers were to contribute instructions for making a stress analysis of a telescope, and the best was to be chosen for use in Amateur Telescope Making-Book One. But nothing fruitful resulted. Thus after going full circle we return to an original hunch that the successful builders, such as Russell Porter and Robert Esch, usually arrive at a sufficiently rugged mounting by intuition and judgment, while those who feel they need instructions would probably reject the stress-analysis answers anyway.

The Esches found that their neat one-legged support for the diagonal mirror resonated in vibration when the Kansas "zephyrs" whistled down the telescope tube, blurring the image. They substituted a more conventional three-legged support spider.

Robert writes: "We are most proud of the simplicity of the driving controls, now that we have added a drive. The drive uses a synchronous ball-bearing motor of ~20 horsepower and 1,800 revolutions per minute, geared through a 96-3-~3-30-100 gear combination to give a ratio of 2,592,000 to 1. While this does not give perfect sidereal time, it would be wasteful to buy special gears for a closer approximation." Karl adds: "I set the telescope on Sirius and went indoors for an hour to blot up heat and on returning I found Sirius still in the field."

Walter J. Semerau, whose astrographic camera and still larger guiding telescope are shown on page 112, is a professional scientific instrument maker for whom telescope making is a hobby. Before he built these instruments he had made some simpler telescopes. He writes:

"For photographic work a telescope must be as rigid as a rock throughout. The mirror is mounted on a nine-point support system in a cast-aluminum cell attached to a 60-inch length of 14-inch aluminum tubing with walls one eighth of an inch thick. One half of a rebuilt 10-power binocular with illuminated cross-hairs is attached to the side of the main tube and is used for wide-angle photography. If photographs are to be made simultaneously with it and the reflector, the guiding is done with a special guiding eyepiece on the telescope. This eyepiece receives light from a single star near the edge of the field, lengthens its own focus with a tiny negative lens, and reflects it into the eye with two tiny diagonal prisms. This guiding eyepiece has a 1-inch focal length and is equipped with illuminated cross-hairs. These must be parallel to the motion of the star and at right angles to the declination."

Roger Hayward comments on this telescope: "Semerau has a very professional instrument. The only weak spot is the guiding eyepiece, which is fixed. There are lots of things one would like to photograph for which there is no convenient star at just the right distance and spacing to fit his instrument. Therefore guiding eyepieces should be arranged to be fixed at any orientation around the plate holder. When I built my photographic attachment, I arranged things so that the plate holder and eyepiece could be rotated around the line of sight. The professionals use two guiding eyepieces which are clamped to the plate holder. They are adjusted to fit two stars so that the plate holder can be set aside with the eyepieces still attached and the exposure continued at some future time. The two eyepieces insure replacing the plate holder in both the same orientation and direction. It is also more convenient if, as Semerau states, the cross-hairs are parallel to the motion of the star and at right angles to the declination, but I have guided the 100-inch telescope at the coudé focus with the angle between the cross-hairs and the right ascension and declination motions changing over a period of two hours. It can be done."

Bibliography

AMATEUR TELESCOPE MAKING. Edited by Albert G. Ingalls. Scientific American, Inc., 1952.

AMATEUR TELESCOPE MAKING-ADVANCED. Edited by Albert G. Ingalls. Scientific American, Inc., 1952.

AMATEUR TELESCOPE MAKING-BOOK THREE. Edited by Albert G. Ingalls Scientific American, Inc., 1953.

ALGAE CULTURE: FROM LABORATORY TO PILOT PLANT. Edited by John S. Burlew. Carnegie Institution of Washington, 1953.

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