The method of inquiry exemplified by the present work is only one of a number of ways in which empirical research on the trade cycle may be carried out. By subjecting a single brief period to close study, we are enabled to do as full justice as the evidence permits to the complexity of the fluctuations experienced, and to avoid the dangers of over-simplification which are liable to result from attempts to impose too uniform a pattern on the history of fluctuations in different periods. On the other hand, an inquiry along the present lines does not by itself permit us to assess the place of the fluctuations studied in the longer-run evolution of the national economy nor to discern changes in the cyclical process itself over time. Extended comparisons of the 1830's with other periods are accordingly not entered into in the following pages. I hope, however, that the reader will consider that I have provided material from which such comparisons may usefully be made.
The general line of approach adopted is 'quantitative-historical'. I have endeavoured to make full use of such statistics as are available, including both continuous series and more isolated indicators, but have not engaged in elaborate econometric manipulation which the uneven coverage and unreliability of the figures would render inappropriate. At the same time I have drawn largely on 'literary' sources. The amount of material available for the study of so remote a period is, of course, lamentably inadequate when compared with that available for the study of the trade cycle in more modern times. In particular, statistics on the volume of production are extremely defective, and no amount of future research is likely to succeed in making them otherwise. But our sources are capable of telling us a good deal -- more, perhaps, than has always been realised. Moreover, it cannot be said that the material relevant for the study of the trade cycle in the earlier part of the nineteenth century is yet anything like exhausted. It has repeatedly been brought home to me in the course of my work that the historian of the trade cycle should ideally make himself expert on all aspects of the economy he is concerned with; no branch of economic history is irrelevant. In practice, of course, this is an unattainable ideal, and I have had for the most part to rely on the more readily accessible sources. When further specialised studies, based on business records and similar sources, dealing with such subjects as the organisation of trade and payments between Britain and her various overseas markets and the evolution of particular industries and regions, have been made by scholars aware of the cyclical problem, the task of the student of trade-cycle history will be substantially lightened, and his chances of arriving at true and valuable conclusions will be correspondingly enhanced.
It remains for me to express my thanks to those who have assisted me by their advice and suggestions. I am indebted to Professor W. W. Rostow for what I have learnt from his published writings and from discussion with him on nineteenth-century trade cycles generally, and also for calling my attention to a number of sources of information which I should otherwise have overlooked. Professor A. H. Imlah's work on import statistics forms the basis of much of what is said in Chapters III, VI and VII, and my thanks are due to him for . . .