The subject of experiment was our Muscat vinery. This house is worked in connection with four other houses, is heated with hot-water pipes, and the heat can be turned off by a valve in the next division, so that it is conveniently placed for the experiment. About the end of February the outside border was covered with 18 inches of litter and leaves, and a ridge of leaves only was laid on the inside border. The Vines were started fairly at the beginning of March, up to which time no fire-heat had been applied; but from March 1st till April 8th, the hot water was turned on every day at 6 o'clock a.m., and turned off again between 1 and 2 o'clock p.m. The day temperature ranged from 80° to 85°, the thermometer, as a rule, falling to 45° in the morning - sometimes, but not frequently, falling as low as 40°. By April 8th the bunches were well out, and most of the shoots stopped; and a longer and higher day temperature being desirable with the longer day, the heat was not turned off till 8 o'clock p.m. on that date; but finding the temperature of the house was much higher in the morning than was anticipated, the heat was, on the following day (9th), turned off at 6 p.m., being turned on at 6 A.M. as usual; and this rule was adhered to till May 10th, except on two or three occasions between the 19th and 26th of April. The weather at this time was frosty, with frequent falls of snow or sleet; and the risk being too great, the heat was turned on for one hour in the evening - from 9 till 10. On these occasions the lowest temperature was registered, showing the precaution was necessary - otherwise 45° was the allowed minimum, but this was never reached, as, excepting at the date referred to, the outdoor temperature was seldom much below 40°. No account was kept of the day temperature, but as the weather was fine and bright during nearly the whole of the time, it was seldom that less than 85° max. was recorded, and not unfrequently 92° or more, so that I have for comparative purposes given the mean day temperature at 87° in the following table, as being probably very near the mark: -

Temperature Of Muscat Vinery

Recorded by a "Negretti and Zambra" self-registering thermometer, fractions omitted.

Average lowest temperature, 54°; day, 87"; mean of 33 days, 70°.

I send yon a sample bunch of Raisin de Calabrica and Muscat of Alexandria. When Muscats do not set, fruit falls off at once, like Peach-blossom, leaving the spurs of the bunch quite naked; but, in the samples sent, nearly every berry seems to have set, even to the extremities. In fact, our Muscats never set so well before. The reason why the night temperature never fell below 50° was, no doubt, owing to the bed of leaves in the house giving off heat. The hot-water pipes were generally cold by 9 or 10 o'clock every night, the thermometer fluctuating, as a rule, between 65° and 58° at the same time. I think the results go far to show that a frequent minimum temperature of 45° would have been borne with impunity, and possibly an occasional descent to 40° would have been harmless. Let it be remembered, however, that the Vines were treated to a low night temperature from the beginning. I hope no one will experiment by dropping the temperature of their vinery when the Vines are in flower, after having been •pushed on to that stage in a high temperature. I may state that the Vines were drenched copiously with clean soft water through a fine syringe five days out of the seven while in flower.

Had the usual high temperature of from 70° to 75° been given, in all probability just double the quantity of coals would have been consumed.

The bunches sent were cut from the centre of the house, 10 feet or more from the pipes, and are fair samples of the crop. It is further worth while remarking, that no time seems to have been lost. The vinery was started at the same date as last year, and the crop is just as forward now. Our late vinery, just about coming into flower, has been treated in the same way, and, so far as appearances go, with the same good results. It may be interesting to those who reckon much upon such matters, to compare the mean temperature in the above table with the temperature of the favourite climate of the Vine in spring.

Wortley. J. Simpson.

[The two bunches of Grapes received from Mr Simpson were as perfect examples of thorough "setting" as could possibly be imagined. Now that Mr Simpson has replied twice to "D. J.'s" criticism, we think the subject had better drop as between them at least, especially as Mr Simpson does not wish to return to the subject again. - Ed].