Heretofore unpublished enthalpy data which were used in the derivation of smooth enthalpy and heat-.capacity data for NBS SRM 720 (a-A1, 2 0, heat capacity and enthalpy standard) are presented along with some details of the high-temperature experiments. Recent NBS low-temperature measurements on SRM 720 are smoothed by a least-squares spline technique and a revised table of certified values for enthalpy and heat capacity of a-Al,() from 10 K to near the meltng point (2250 K) is presented.

Th e re lat ive e nth a lp y of NBS S ta nd ard Re fe re nce Matcr ia l No. 720 (99.98 perce nt pure. s in glec rys ta l a· AI, O". a ca lorim e tri c hea t-ca pac it y s tandard ) was meas ured ovpr th e range 273 to [173 K by th e drop me thod us ing a hi ghl y prec ise Bun se n ice ca lo rim e te r. Entha lpy d a ta ove r th e s ame te mp e ratun: int e rv a l we re o bt a in ed a lso o n th e Ca lorim etry Co nfe r'e nce Sa mpl e of thi s s ubs ta nce. T hese res ult s a re be lieve d to be more acc ura te th a n s imi lar NBS res u lts o n th e la tt e r sa mpl e pub lis hed in ] 956. a nd s how no s ig n ifi ca nt di sco ntinuit y with th e NBS data on th e sa me s ubs ta nce tha t cove red th e ra nges 13 to 380 K and ] · 173 to 2257 K. Th e ave rage deviation from th e mean for a ll e nt ha lpy meas ure me nt s o n th e S RM 720 s amp le was 0.0 17 pe rce nt , and the s mooth e nth a lpy valu es rl c rive d from th e data were es tim a te d to be acc ura te to 0.1 pe rce nt. Th e preca uti o ns obse rved in o rd e r to minimi ze meas urin g e rrors a re d esc ribed in detail. Th e dat a are co mp a red with many se ts o f th e mos t re li ab le pub lis he d data ava il ab le and new reco mm e nd ed va lues for the th er mody na mi c fun c ti o ns of a·A I, O" a re prese ntt'd for th e int e rv a l 0 to 1200 K. Key wo rd s: Alumina; a luminium ox ide; co r u ndum : drop ca lo rim e tr y: c nth a lp y; hea t ca pac it y s ta nd ard; s pe c ifi c hea t : s ta nd a rd re feren ce ma teria l; sy nt he ti c s apph ire; th ermodyna mi c function s.

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We report precise measurements of the relative enthalpy of polycrystalline YBa2Cu307 q at high temperatures (273 K & T & 700 K). From these data, we determine the lattice and electronic contributions to the specific heat. We find that the specific heat of the charge carriers follows the temperature dependence of a Fermi liquid with a Sommerfeld constant of 25+3 mJ/mole K'. By comparing our data to measurements made at low temperatures, we determine that the electron-phonon coupling is strong in YBa&Cu307 z and adequate to account for the high transition temperature.