Each.'TOttical interspace represents one degree Iiahtenheit, and the .fractional parts of a degree are indicated as exactly as possible in the plotting of the curves. 'Each fifdi 

 de«ee is teptesented.by a slightly heavier line. The transverse interspaces inclosed by flie heavier lines represent periods of ten days each, as indicated by the dates on flie 

 lefiiaul side oX the 'plate. The lighter transverse lines, intermediate betjvfien the heasaeiT ones, are Intended to represent flie mean of each ten days, and the curves of tempec- 

 attlEB atfi plotted vdth reference to tliese lines. The Ieft-Jhand,-cer£cal division is devOtesl to the. air teTnpetatnres for I.8SI^, x.aa2 and i SS3, the middle division to die surfacei 

 "(Saiier tempBiaTxiteS for the sanie years, tlius pBrmitting of a comparason of flie two; a,nd fhe raghtjhand. dimslxm to tliE -water temperatures for' 1884 and 1S85. 



