Six works by Arshile Gorky, the passionate and lyrical Armenian-born New Yorker, have been bought and placed on view here by the National Gallery of Art.

Though Gorky is best known for the fluid melodies of his late abstractions, the most compelling picture in the Gallery's million-dollar purchase is based upon a photograph treasured by the artist. The painting was begun in 1926; Gorky worked on it 10 years. Drenched with love and mourning, obsession and nostalgia, "Portrait of the Artist and His Mother" is one of the touching double portraits of our time.

Arshile Gorky suffered. His life began, and ended, in appalling misery.

He saw his mother starve to death when their village in Armenia was besieged by the Turks. Gorky was 16, when, in 1920, he disembarked at Ellis Island. In January 1944, Gorky's studio burned. In February of that year he discovered he had cancer. In June of 1948, a car crash broke his neck and paralyzed his painting arm. The next month his wife left him. A week later Gorky hanged himself. He was only 44. Yet despite his pain and poverty, his paintings seem to sing.

Accompanying the moving double portrait is a square-off pencil study for the painting. The other four new Gorkys acquired by the Gallery all read as abstractions. The purchase, made with monies from the Ailsa Mellon Bruce Fund, gives to the Gallery a survey of the painter's work few American museums are able to surpass.

Gorky, who once shared a studio with Willem de. Kooning, gave himself wholeheartedly to the new New York painting. He believed in the new. Yet despite his innovations, his carefully made pictures are fully as conservative as they are prophetic.

He looked like a Bohemian, but though his black eyes flashed and his black moustache drooped, Gorky was no radical. He carried in the pocket of his huge black overcoat a little well-thumbed booklet of Ingres reproductions. He haunted the museums. He worshiped, and he learned from, Uccello, Grunewald, Cezanne, Seurat, and the painter that he called "that man Pablo Picasso."

"I shall resurrect Armenia for all the world to see," he wrote, "and when we return to clay as we all must, then perchance they might say, 'As a son of the Armenian mountains he offered his modest share to the accumulation of our world's great culture.

Innovative as they are, his paintings are in spirit somewhat more old fashioned than those of his contemporaries, de Kooning, Hofmann, Pollack. He objected to what he called "the deification of novelty." Because he filled his art with dreams, he was seen as a surrealist, but he refuesed that label.

Despite that disclaimer, Gorky always trusted reveries and dreams, and it is clear that he learned much from the friendships he formed in the 1940s with the surrealists Matta and Breton.

The real plants he saw, and those that he remembered from his childhood mingled in his art: "Apricots, peaches, apples, grapes. The rich colors of . . . our grains and flowers. Always I try to duplicate the colors of Armenia in my work."

Gorky made two versions of the portrait with his mother. One is in New York at the Whitney Museum of American Art. Its silvery colors are far cooler than the apricots and plums, the sun-kissed, Mediterranean hues of the Gallery's new painting. Building so that it looks across the room at a huge rose-period Picasso. The installation works.

The East Building has for months felt peculiarly empty, in part because much second floor exhibit space was being used as corrider.That admirable exhibit space has now been redesigned, and carpeted, and filled with splendid pictures, Picassos, for example, as well as borrowed Rothkos, Stellas and de Koonings. A borrowed Gorky self-portrait also is on view. With the new installation the East Building's second floor seems a much improved place for seenig art. CAPTION: Picture, Double portrait of artist Arshile Gorky and his mother; Illustration, the pencil sketch for the 10-year work.