Natural ventilation effects on temperatures within Stevenson screens

Thermometer screen properties are poorly characterised at low wind speeds. Temperatures from a large thermometer screen have been compared with those from an automatically shaded open-air fine-wire resistance thermometer. For the majority of 5-minute average measurements obtained between July 2008 and 2009, the screen and fine-wire temperatures agreed closely, with a median difference <0.05◦C. At low wind speeds however, larger temperature differences occurred. When calm (wind speed at 2 metres, u2, ≤ 0.1 m s−1), the difference between screen and open-air temperatures varied from −0.25◦C to +0.87◦C. At night with u2 < 0.5 m s−1, this difference was −0.14◦C to 0.39◦C, and, rarely, up to −0.68◦C to 1.38◦C. At the minimum in the daily temperature cycle, the semi-urban site at Reading had u2 < 1 m s−1 for 52% of the observations 1997–2008, u2 < 0.5 m s−1 for 34% and calm conditions for 20%. Consequently uncertainties in the minimum temperature measurements may arise from poor ventilation, which can propagate through calculations to daily average temperatures. In comparison with the daily minimum temperature, the 0900 UTC synoptic temperature measurement has a much lower abundance (5%) of calm conditions.

Two unpublished letters of Robert Louis Stevenson

This article prints and discusses two uncollected letters by Robert Louis Stevenson to the publishing firm of Chatto & Windus, concerning his book Memories and Portraits.

Aesthetical and narrative uses of the trench in the Hollywood cinema of 1918-1930

Throughout history of painting, the representation of landscape has been considered a laboratory for the human gaze on the world. The First World War and its new approach to the battlefield altered deeply the classical forms of representation, and replaced them with a mechanised and fragmentary vision, which was related with the development of photography and cinema. As Vicente J. Benet has analysed, Hollywod cinema used these deep changes in its filmic versions of the conflict, although it organised them following a narrative logic. In this text we intend to study how the battlefield and, particularly, the trench, are inserted in this logic of the history of landscape painting. We do so through some Hollywood films from the period 1918-1930. Firstly, we approach the trench as a composition value which can structure the image and guide the camera movement. In the second place, we study how it creates a dialog between its inside, melodrama scenery, and the outside, battlefield and danger. In both cases, we conclude that the trench as a form and as a narrative element plays a structuring and integrative role with the storytelling logic.