Finding and enjoying the wonders of nature almost anywhere, from city to forest, is the subject of a recently published, very good book. Another new one is about fragrant concoctions and tells how to ereate your own potpourris, incense, toilet waters and sachets.

"The Walker's Guide to Nature," by Connie Krochmal and Arnold Krochmal (Drake, 160 pages, well illustrated, $5.95 paperback.)

The Krochmals describe the wonder of watching bits of green struggle to survive in the cement of ueban areas. They tell of two large green caterpillars they found on a walking trip and house in a mayonnaise jar with soil and pine cuttings. If the caterpillars turn into moths in the spring, they'll be set free.

The Krochmals also describe the wonders of desert and beach, and, as well the unlimited opportunities for nature studies in all backyards, large or small.

The cheapest way to feed birds, squirrels and chipmunks, according to the Krochmals, is to buy 50 pounds of chicken scratch and enrich it with five pounds of sunflower seed. Over a period of six months, they attracted a number of fascinating visitors, migratory and semipermanent, and even saw a black mole groping his way along the surface.

"Potpourri, Incense and Other Fragrant Concoctions," by Ann Tucker Fettner (Workman, 137 pages, illustrated, $2.95 paperback)

The author is a writer, filmmaker, director, teacher and scent-maker.

The effect of fragrance on one person may be entirely different on another, she says. Ten people inhaling the same aroma would probably perceive and be affected by it in as many different ways, so much does a smell depend on the mental association it evokes.

How can one describe a perfume? People have tried for thousands of years. fragrance has been equated with the musical scale, with the highest note of the treble clef assigned to civet. The lowest tone was said to correspond to patchouli. Each chord formed a bouquet. The bouquet of C chord in the bass was formed of sandalwood, geranium, acacia, orange flowers and camphor; G chord in the treble was sweet pea, violet, tuberose and orange flowers again.

Animal and other similar odors, such as costus root and amberette seed, add sex-stimulating quality to perfumes. They are blunt and alkaline and may have a fatty or waxy overtone. In perfumes they impart a low base note, a dark quality.

Anti-sexual or refreshing fragrances are in direct contrast to animal odors. They are the green resin fragrances produced by the saps and leaves of plants, by camphors, pines and some of the mints. These fragrances, when used as the signature of a product, give it a healthy clean feeling. Most aftershave lotions are formulated with this in mind; the signature is a wake-up note rather than a relaxing one.

Important for house plants this time of year: Sponge and clean their leaves once or twice a month. It is especially desirable for foliage plants such as the split leaf philodendron (Monstera deliciosa), rubber plant (Ficus elastica), umbrella tree (Schefflera) and mother-in-law plant (Dieffenbachia.)

Washing the leaves opens up the pores and helps prevent a buildup of insects.

Two kinds of insects are likely to be present on plants in the warm, dry atmosphere of the home: spider mites and aphids (plant lice). They such juice from the plant and heavily infested plants become stunted and may die.

Because of their tiny size, detection of spider mites is not easy for the unwary, and they may do a lot of damage before being discovered. When searching for them, it is wise to use a magnifying glass. They multiply rapidly, usually on the underside of the leaf. If there are many of them, silky webbing may be visible.

Aphids come in several colors, are larger than mites and easier to detect. They tend to cluster on the undersides of leaves or on young tender leaves and steams of flower buds.

To wash the leaves, use a sponge or soft cloth and water at room temperature eith a small amount of very mild soap added (no detergent).

Both insects and their eggs will be removed by this treatment if it is thorough. It may not be completely effective against a heavy infestation, but repeated Handle the leaves gently. Rough treatment may cause the edges to turn brown.

A good shine can be achieved by rubbing the foliage gently with softcheesecloth or a fien camel's hair brush.

The natural oils in the leaves should produce a high glass. If they don't try ordinary milk. It contains just enough fat to shine green leaves.

Malathion, an insecticide, is often recommended for contrl of mites and aphids on house plants. It may be effective with aphids, but mites seem to have developed resistance to it. Besides, it is never a good idea to spray an insecticide in the home if it can be avoided.