Adsorbed monolayer specific heat experiments have relied to date on exfoliated substrates with large sample areas but complicated geometry. Using micro-circuit fabrication techniques, we have instead constructed an ac calorimeter from a small cleaved sheet of graphite. Total heat capacity at 3 K is 45 multiplied by 10** minus **9 J/K, with a film contribution of approximately 1 multiplied by 10** minus **9 J/K. Despite a sample area reduction of the order of 10**6, we are able to duplicate data taken with some exfoliated graphite substrates.