Report on the Cultivation of Potatoes. 511 



Under this supposition, the value of the practice of taking' 

 turnips as a preparatory crop to potatoes lies in the facilities 

 which it affords the farmer to thoroughly clean and stir his land 

 for a year and a half preceding the critical period when the 

 potato-fungus usually attacks the haulm. On this point the 

 replies of Mr. Knowles, and his addendum on his method of 

 cultivation of turnips, leave nothing to be desired. They show 

 clearly that no opportunity for stirring the land is lost, and 

 that the land is not allowed to rest long enough together to 

 allow of the growth of any quantity of what is commonly called 

 " filth." 



The immunity enjoyed by iSIr. Knowles and ^Ir. JMyatt may 

 not be in the least degree due to the fact that they take potatoes 

 after turnips or savoys. " Post hoc " is not necessarily '■'' propter 

 hoc^^ as we are continually reminded ; and " after turnips " may 

 very likely not be synonymous with " because of turnips," even 

 in their case. Then, even if the protective influence of the fallow 

 crop could be proved, we must be cautious about generalising too 

 hastily ; for " one swallow does not make a summer," and there 

 may be other conditions which may contribute very materially 

 to the production of what must, under any circumstances, be 

 considered a very remarkable fact — the immunity of their crops 

 from potato-disease for a number of years consecutively. 



It may be suggested that other circumstances, either of soil, 

 climate, locality, or cultivation, might account for the absence of 

 potato-disease from these farms ; and, with a view of estimating 

 the probability of this view, I visited both of them. One farm 

 (Mr. Knowles's) is on the shores of !Morecambe Bay ; the land 

 has been reclaimed from the sea, and is a very light grey soil, 

 containing 86 per cent, of sand, more argillaceous matter than 

 would at first be thought probable, and some lime. It is exceed- 

 ingly light, and of great depth (but, nevertheless, drained), and, 

 altogether, a very remarkable soil under any circumstances ; but 

 it is more remarkable still when seen, as I saw it in July, in a 

 season like the present one, bearing heavy crops of wheat and 

 barley, and most promising crops of roots and potatoes. Dr. 

 Voelcker has undertaken the analysis of this soil, and will, 

 probably, have something to say about it in his next Report. 

 Mr. Myatt's land is a somewhat light loam on gravel (also 

 drained), situated in the vale of Evesham, and presenting no 

 features that call for special remark. The circumstances of soil, 

 locality, and climate of Mr. Myatt's farm are thus quite different 

 from those of Mr. Knowles's. The details of cultivation are also 

 dissimilar, except in one respect, viz., that the drills for late 

 potatoes are 36 inches apart in each case. This, of course, assists 



