Graphs, rate of issue of gas and relation of zenith to ordinates by unknown artist Plate 44, figures 2 and 8 showing a graph of the rate of issue of gas from the flame used in Bunsen and Roscoe's experiments and a graph of the relation of the zenith distance to the ordinates. Inscribed with publication and plate details. Figure 2 is drawn separately and pasted onto the page with figure 8. Not signed. The manuscript for this paper is wanting. Subject: Physics / Chemistry Published in Philosophical Transactions as part of paper titled 'Photo-chemical researches.—Part IV' by Robert Wilhelm Bunsen and Henry Enfield Roscoe. Received and read by the Royal Society on 26 May 1859. [1859]