The Adderley brothers have had a career on records that is not much more than a year old, yet in that time they have shown an amazing musical potential, expanding both in public recognition and in their own musical capabilities.

Nat Adderley, in particular, seems to have matured considerably as the result of a confidence acquired during the first few months playing in the big-time jazz circles of Basin Street and The Bohemia. As his brother Julian puts it, "Nat has discovered he is more capable than he realized himself; his range is expanding and there are moments when he sure sounds like Clifford Brown."

This new set of Adderley performances marks the first appearance on records of the actual group with which they have been playing the night clubs lately. Their regular touring personnel consists of Nat and Julian plus Junior Mance on piano, Charles Wright on drums and Sam Jones on bass. Al McKibbon, best known as a member of the George Shearing quintet for the past several years, is the bassist on Number 251, Sam's Tune, The Fat Man and The Nearness of You.

Number 251, which opens the set, is a happy-sounding original written especially for the group by Jackie Byard, a pianist and tenor saxophonist who works witb Herb Pomeroy's group in Boston. Solos by Nat, Cannonball and Mance.

Sam's Tune is a simple blues, starting with four bars of riffing that are then repeated a fourth higher. A surprise arrives in the shape of a cello, played by Sam Jones. Though he has only had about a year's experience in the pizzicato jazz cello approach, Sam reveals here that Oscar Pettiford may have a serious competitor in the near future.

Bimini, a haunting minor theme written by Nat, is named for an island in the Bahamas where the Adderleys used to go deep-sea fishing. Again, alto, trumpet and piano are featured in the solo roles.

The Fat Man was composed by Jerome Richardson, the saxophonist and flutist well known in New York jazz circles and heard as a soloist on several EmArcy long plays. Naturalty it is named for Cannonball, who establishes the minor riff theme, with its two- beat feel, while Mance gaily fills the gaps between phrases. Nat is particularly effective in his muted solo here.

Sermonette, which concludes the first side, has a "churchy" theme representative of what might be called the "modernized ancient" school of jazz composition, of which Horace Silver's The Preacher was an earlier example. Again the rhythm has a gently rocking two-beat accent with Jones' bass as an effective underline.

Jackleg, a 16-bar minor theme played in unison by the two horns, was written by Samuel Hurt, a trombonist who used to play with Dizzy Gillespie's big band. A jackleg preacher is one who has no church of his own, but walks around preaching on street corners. You can hear this flavor both in the melody and the construction, which uses breaks on the middle four bars, along the antique but perennial lines established in the early jazz days by such tunes as How Come You Do Me Like You Do? Mance sounds very Horace Silverish in his excellent solo here, and Jones' eloquent bass precedes the final fading theme.

The Nearness of You, a Hoagy Carmichael standard, opens with a melodic Cannonball solo. Nat improvises in a peppery, multi-noted style; Wright doubles the rhythm while the bass retains the original slow tempo. Toward the end, Cannonball and Nat indulge in a little family fun with a quote from Alouette and generally satirical atmos phere that reminds us of the Adderleys' always latent sense of humor, a welcome element in any jazzman's personality.

Rattler's Groove, another original by Nat, was named, we were told "after our college football team. The team's mascot was a rattlesnake and they called us the Florida Rattlers".This is a boppish opus in which Julian, Nat and the other Julian are very much at ease; Wright gets a solo spot in the bridge of the last chorus.

Hayseed is another "kidding on the square" composition, at bright tempo -"We tried to depict country, folk-type themes," explains Cannonball. The rhythm section, as it has in the entire album, really wails throughout this consistently swinging performance.

We feel sure that if you have met the Adderley brothers on one of their many successful night club engagements, you will be happy to find them preserved intact on records and reacquaint yourselves with them on these sides. Of course, if the long play marks your first encounter with the jazz contributions of this outstanding quintet, we hope the situation will apply in reverse by leading you to your local bistro the next time they pass through town.