+#' The private field .data is a list where each cell contains the variables for a period
+#' of time of 24 hours, from time P+1 until P the next day where P is an integer between
+#' 0 and 23. .data[[1]] refers to the first measured data (serie and exogenous
+#' variables): the corresponding times can be accessed through the function
+#' \code{getTime()} below. Each cell .data[[i]] is itself a list containing five slots,
+#' as described in the 'field' section.