TENDER PLANTS AFFECTED BY FROST. 305 



Salpig]o5sises will grow and flower iu the garden in a satisfactory 

 manner, provided they are planted out from tlie pots about the 1st of 

 June, in ricli dry soil, and a slieltered situation ; bat in my opinion, and 

 my success bears me out, the situation to show them to the greatest 

 advantage, is in the greenliouse amongst Cockscombs, Balsams. Tri- 

 verania coecinea, and some species of Gloxinia. Ihere they will flower 

 admirably, and with proper management produce seed in abundance. 



I usually sow a little seed in September, for the purpose of having a 

 few early flowering plants. They require to be kept througli the winter 

 in the stove, close to the glass, in small pots, and then managed as to 

 soil, potting, &c., as the spring-sown plants, and they flower finely in 

 April, May, and June. 



I think, too, rich soil very injurious : the plants often take the pet, 

 and die off by the ro(jts, in it. I have frequently seen plants witii fine 

 healthy leaves and flowers, dying gradually upwards. I cannot account 

 for this disease, excepting by the soil being too rich. 



To be certain to procure seed from Salpiglossis atropurpurea and 

 Barclayana, it is necessary to impregnate them artificially ; whilst picta, 

 straminea, and their varieties, seed freely without any care. Upon 

 examination, however, this apparently strange circumstance may be 

 easily accounted for : the pistil in those species is considerably elongated, 

 and the stigma on its sunniiit is of a curious boat- like shape ; and as the 

 flowers stand quite erect, the pollen falls to the ground without effecting 

 its office, unle>s by chance some friendly insect assist in the business, 

 which, whatever it may do in their native situation, is not to be expected 

 in our greenhouses. 



By impregnating with different sorts, I find they sport into various 

 and beautiful shades of colour and size ; and I have no doubt many 

 sorts will run one into another, which satisfies me tliat most of the kinds 

 now ranking as species, will have to be reduced to mere varieties. 



TENDER PLANTS AFFECTED BY FROST. 



BY SENEX. 



Amateur cultivators of tender plants, especially those who have but 

 little of glass protection, are liable to the casualty of injury from frost, 

 and as some of my brother cultivatoi-s may not be aware of an antidote 

 to such misfortune, I forward the following particulars, trusting they 

 may be of service ; and as winter is approaching, an early insertion is 

 requested. 



ilEAT, or Caloric, exists in two states, viz., latent and perceptible ; 

 when any two substances of different temperature come in contact with 

 each other, the temperature of the one is raised, and that of the other is 

 lowered, until the two substances become equal, and if they are of 

 equal density, tlie temperature will be a mean one — this is provided that 

 neither of these substances undergo a change from solid to fluid, or from 

 fluid to gaseous. In this case a great quantity of perceptible heat will 

 be consumed, and converted into latent heat ; and if the change is from 

 gaseous to fluid, or from fluid to solid, perceptible heat will be produced 



Vol. xviii. No. 48.—N.S. 2 c 



