Notwithstanding what has already been written and said on this subject, by men who are celebrated for the quantity and quality of their Grapes, there still exists a doubt in the minds of some Grape-growers regarding what is the best temperature to maintain at night during the time the Vines are in flower, especially in the case of Muscat and other shy-setting varieties.

Of late it has been contended by a few writers on Grape-culture, that it is not necessary for the successful setting of the fruit to subject Muscats when in flower to as high a night-temperature as that recommended in books treating on the culture of the Grape-Vine; and that as good, if not better, results would follow, both as regards the set, in the first instance, and the ultimate finish and flavour of the fruit, if, during the various stages of growth, the Vines were treated with a much lower temperature during the night than is generally practised. And not only so, but it is also contended that a low night-temperature is conducive to health, longevity, and fruitfulness in the Vines; and by its adoption they are kept free from certain insects that prey upon them at some places when treated to a higher temperature in the night.

The foregoing is a short summary of the advantages said by the advocates of the "cool system" to be derived from an adherence thereto in the culture of the Grape-Vine. And at first sight it might appear that their claims were indisputable. For instance, on the score of economy alone, one would think the cooler system of Grape-growing had a great advantage over the hotter. By the former system we are told that a saving in fuel and labour is brought about, and that it also prevents insects from attacking the Vines during the growing season, and thereby the cost of "red-spider and thrip antidote" and other insecticides is saved. The economical argument, however, is more apparent than real, as we will see presently. Speaking of red-spider and thrips, however, leads me to remark in passing, that when these insects infest Vines year after year, it is an evidence that there is a weak link - other than high night-temperature - somewhere in the chain of conditions or management under which the Vines are growing.

Referring again to the "cool system," it is much to be regretted that, when tried against the hotter - all other conditions being equal, and the test of superiority being the finish, flavour, and keeping qualities of the fruit produced by the respective systems - it is, to use a sporting phrase, nowhere. I do not say this without "having given both ways a fair trial" with several sorts of Grapes. Where large properly built bunches, having large even-sized berries of good colour and excellent flavour, are wanted, a higher night-temperature must be maintained from start to finish than that recommended by the defenders of cool treatment.

And now with regard to the best degree of temperature to maintain day and night, when the Vines are in flower, with a view of securing a satisfactory set of the fruit. In my experience, I have found that the best results follow, in the case of Muscats, when the night-temperature is kept as near 70° as possible, with a rise of from 10° to 15° during the day, according to the amount of sunshine prevailing. I may state, however, that Muscat of Alexandria, and what is called Bowood Muscat, are the only two kinds that I ever experienced any difficulty with in the matter of setting of the fruit. And in the case of these Grapes, I have never been able to get them to "set so well that the berries become wedged together by the thinning period." Still, until this year, I managed to have as shapely bunches as most people, and superior in other ways to some that had been thought worthy of being publicly exhibited.

I will now tell what, in my opinion, was the cause of the Muscats setting worse this year than usual. Before doing so, however, I had better say that the Muscat-house here contains ten Vines - that is, seven Muscats, one Trebbiana, one Syrian, and one Raisin de Calabrie - all of them being very vigorous; and having been thoroughly ripened in 1880, they were in first-rate order for starting in the first week of February this year. Well, as before stated, the Muscats, although treated to the orthodox temperature, never set so well as I would like them to have done; and I determined last January that I would try them on the "cool system." The buds swelled and started into growth with great regularity all over the canes, and a magnificent "show" for fruit-followed. Everything seemed to be right until the period arrived when the berries should have been set, when, to my amazement and chagrin, they dropped off in showers; and such ragged jack-like bunches of Muscats as we have had this year has not been seen in these parts before. Now, as regards the other varieties of Grapes in the same house, the set was all that could be desired, which, in my humble opinion, proves that Muscats require a higher night-temperature than 50° to insure a good set.

I will now refer to another house containing the same number of Vines - that is, three Gros Colmar, three Lady Downes, two Alicante, one Gros Guillaume, and one Mrs Pince. In this case the set was all right, and the bunches and berries are of good size, but the colouring process did not commence until three weeks later than in former years. At the present time the colour is as good as needs be, as a bunch of Gros Colmar sent to the Editor will prove [Jet Black - Ed.]; but none of the kinds mentioned are ripe in the right sense of the word, consequently they are keeping very badly, and the bunches are fast becoming in looks like their ragged friends the Muscats in the adjoining house. And thus we are now squandering in the vineries more than we economised in the stoke-hole earlier in the year.

It is of as much importance to those of us who have to supply Grapes every day for ten months of the year, to know the conditions that are most conducive to them keeping plump and sound the longest period, as it is to know the conditions under which the best set of the berries are secured; and to insure them keeping well, they should be thoroughly ripe before the days have crept in much - that is, not later than the first week of September. After this time Grapes will improve in colour; black Grapes will become blacker, and Muscats and other white sorts will become a bit yellower, but neither black nor white will get much riper. True, the flavour may improve or change after this time, but this is not the kind of ripening that tends to their keeping fresh, sound, and plump during the winter and spring months. What is required to enable them to do so is a thorough maturing of the skin, pulp, and seeds of the berries before the sun has declined in power, and the autumn nights have come on, and these conditions cannot be secured under the "cool system" of Grape-growing.

The same holds good in the case of ripening the wood. If it is not solid and ripe about the time mentioned that the Grapes should be ripe, you may fire as much as you like afterwards, but you will not impart to it that fruit-producing ripeness that might have been secured with half the consumption of fuel earlier in the season, when the days were long and the sun powerful. In the case of Grape-growing, the time to economise in the stoke-hole is not during the spring and summer, but during the autumn and winter. In future I intend to start our late-keeping Grapes in the first week of February, and to maintain at night, when they are in flower, "the regulation standard of 70° for Muscats," and 60° for the other kinds; and also to push them on briskly during the early summer months, so that the crop may be thoroughly ripe in the first week of September.

In reference to the quality of certain Grapes when ripened in a high instead of a low temperature, I could quote many authorities to corroborate my own experience, and notably the evidence of your correspondent, Mr J. Simpson, who wrote a few years ago, - "No one, I think, can dispute the fact that late Grapes are better flavoured when ripened early in the autumn under a higher temperature than they are generally treated to. . . . The difference in flavour is so great that they are not like the same Grapes." J. Hammond.