ArgumentMuch of the long controversy concerning the workings of electric batteries revolved around the concept of the contact potential (especially between different types of metals), originated by Alessandro Volta in the late eighteenth century. Although Volta’s original theory of batteries has been thoroughly rejected and most discussions in today’s electrochemistry hardly ever mention the contact potential, the concept has made repeated comebacks through the years, and has by no means completely disappeared. In this paper, I describe four salient foci of (...) its revivals: dry piles, thermocouples, quadrant electrometers, and vacuum phenomena. I also show how the contact potential has maintained its presence in some cogent modern scientific literature. Why has the death of the Voltaic contact potential been such an untidy affair? I suggest that this is because the concept has displayed significant meaning and utility in various experimental and theoretical contexts, but has never been successfully given a simple, unified account. Considering that situation, I also suggest that it would make sense to preserve and develop it as a multifarious concept. (shrink)

We investigate the dynamics of sensory integration for perceiving musical performance, a complex natural behavior. Thirty musically trained participants saw, heard, or both saw and heard, performances by two clarinetists. All participants used a sliding potentiometer to make continuous judgments of tension (a measure correlated with emotional response) and continuous judgments of phrasing (a measure correlated with perceived musical structure) as performances were presented. The data analysis sought to reveal relations between the sensory modalities (vision and audition) and to (...) quantify the effect of seeing the performances on participants' overall subjective experience of the music. In addition to traditional statistics, functional data analysis techniques were employed to analyze time-varying aspects of the data. The auditory and visual channels were found to convey similar experiences of phrasing but different experiences of tension through much of the performances. We found that visual information served both to augment and to reduce the experience of tension at different points in the musical piece (as revealed by functional linear modeling and functional significance testing). In addition, the musicians' movements served to extend the sense of phrasing, to cue the beginning of new phrases, to indicate musical interpretation, and to anticipate changes in emotional content. Evidence for an interaction effect suggests that there may exist an emergent quality when musical performances are both seen and heard. The investigation augments knowledge of human communicative processes spanning language and music, and involving multiple modalities of emotion and information transfer. (shrink)

Our hardware is an electric vehicle, remotely controlled over a citizens band radio link by a PDP-KL10. It carries a black and white television camera whose picture is broadcast over a UHF channel, and received and occasionally digitized by the computer. The vehicle has drive motors for the rear wheels, a steering motor coupled to a steering bar arrangement on the front wheels, and a motor controlling the camera pan angle. Each can be commanded to run forward or backward. There (...) is a potentiometer on the steering and pan linkages which enables them to be commanded to point straight ahead. The mechanical arrangements are crude, the motor speeds are unregulated, and there is no feedback to the computer other than the video from the camera. Overall dead reckoning errors are on the order of 30%. Most of the computer controlled runs so far have been with the camera pointed straight ahead and the vehicle moving forward in two foot increments, punctuated by long pauses, during which the images are processed. (shrink)