Museum statistics show that during the last decade there has been an upward trend in the circulation of travelling exhibitions of works of art and museum objects. It seems impossible to reverse this trend; especially in the face of the increasing popularization of museums and the extension of the educational arm of the museum far afield. Many museum directors, curators, scientists and conservators are rather disturbed with the greater frequency of travelling exhibitions and the obvious increased danger to the safety of works of art. Ideally it would be best for exhibits if they never left their original homes, at least they can then be constantly observed and cared for by trained personnel, and preserved under proper environmental conditions. Much has been written on the desirable museum environmentL2 for the effective conservation of humidityand temperature-sensitive art objects. Certain progress has been made, and several major art museums have stabilized, temperatureand humidity-controlled atmospheres. Unfortunately little effort has hitherto been spent on research into desirable environments for such objects during transit conditions. Some notable studies have, however, been made3•4; these indicate that it is now possible to ship panel paintings overseas if strict attention is paid to environmental control of humidity and temperature at all stages of the trip-that is, from 'museum to museum'. To do so requires a major effort on the part of senior museum officials, scientists, travel agents and customs personnel at border crossing points. Not least in the effort is the requirement of suitable packing against the possible effects of shock, vibration and condensation. The museum scientist and conservator can no longer afford to be indifferent to the needs for better preservation of works of art during travel. In his particular museum there may be an active circulating exhibition programme. It is encumbent upon the scientifically or technically trained museum employee to offer advice, perform research and be otherwise helpful in ensuring the safety of the exhibits in transit. Newer methods of packing must be devised (in this respect much can be learned from the packaging industry5.6) and personnel responsible for packing procedures must receive newer and more extended training. The purpose of this report is to indicate briefly the results of certain procedures which have been successfully used at the National Gallery of Canada, in a country which has a very difficult climate. Some trial experiments with an environmental chamber will be reviewed, and general comments will be made on particularly difficult travel situations. (in the interior of the country), a distance of approximately 3000 kilometres, with outside temperatures as low as 30°C and correspondingly dry atmospheres. Some of the paintings were wax-relined, but most were not; these were, therefore, in the moisture-sensitive category, whence great attention had to be paid to conditions of relative humidity in transit. Likewise the prints and drawings required protection to avoid desiccation. While these works of art had been shipped mainly by air from Holland in light containers it was considered essential to repack the entire exhibition for winter travel. Consultations were arranged with the scientific staff, the packing and handling staff and officials of the National Railroad system to ensure that maximum safety would result. Cases were constructed of top-quality white pine, painted on the outside and carefully lined with a fibre-board material (compressed de-fibred wood pulp) to serve as a heat-insulating and moisture-retentive envelope to surround the painting and graphic art works. All construction materials had been stored inside the National Gallery at the conditions prevailing there; that is, at a relative humidity of 48 per cent and a temperature of 21°C. Under such conditions the equilibrium moisture content (oven-dry basis) for the wood is 10 per cent and that of the fibre-board is approximately 8 per cent. The works themselves were prepacked in kraft paper to afford additional protection.