The physical links by which the stratospheric QBO functions as both an active and passive agent in climate variability are not yet established. Nevertheless, it continues to gain acceptance as an essential element of both empirical and numerical climate analysis and forecasting. A restriction on this activity is the short (since 1950) QBO data record, although there have been several attempts to extend this record using proxy information. In particular, the amplitude of the semi-diurnal harmonic of the surface thermal pressure tide [S2(p)] in the tropics is forced primarily by deep solar heating of ozone in the mesosphere and stratosphere. The fidelity of the transmission of this signal to the surface is affected by various atmospheric conditions; most notably, vertical shear of the wind, and hence, the QBO. Results summarize work aimed at specifying the anomalous structure of lower stratospheric zonal wind shear (ie., the QBO) from historical (pre-1950) surface pressure observations dating back into the 19th century. Whereas prior work of this sort has generally focused on simply showing the presence and bulk periodicity characteristics of QBO variability, the present study considers the extent to which more detailed qualities the QBO may be assessed on seasonal time scales. New results (1) include applications of several alternative methods for extracting detailed S2(p) anomalies from high quality hourly SLP data (back to 1866); (2) considers influence of seasonality of both stratospheric and tropospheric conditions, especially ENSO enhanced seasonality and localized factors affecting upper tropospheric vertical wind shear anomalies and their influence on the S2(p) signal; (3) introduces cross checking of the inferred QBO modes using additional (provisional) associations between the QBO and anomalous broad-scale tropical rainfall, SST and SLP distributions. The inferred directional QBO values are highly consistent with the known set of late 19th and early 20th century direct observations of equatorial stratospheric winds