234 Qf Change of Species. Chap. XIV. 



fends off its Recrements in the fame Proportion like- 

 wife; and therefore requires the lefs of the terrene 

 Nourishment to fupply thofe Recrements. 



This is feen, when a Bufhel of Turneps, mixed 

 with a Quantity of Wheaten Flour, is made into 

 Bread, and well baked : This Bufhel of Turneps 

 gives but few Ounces Increafe in Weight, more than 

 the fame Quantity of Wheaten Flour made into 

 Bread, and baked without any Turneps. This fhews 

 there is in a Turnep very little Earth (which is the 

 mod: permanent Subftance of a PlantJ ; the Oven 

 difcharges in Vapour near all but the largeft VefTels: 

 Its earthly Subftance being fo fmall, is a Proof 'tis 

 maintained by a fmall Quantity of Earth: and, upon 

 that Account alfo, of lefs Damage to the next Crop 

 than another Plant would be, which required more of 

 the folid Nourifhment to conititute its firmer Body, 

 as a Charlock does-, for when a Charlock comes up, 

 contiguous to, and at the fame time with a Turnep, 

 it does fo rob the Turnep, that it attains not to be of 

 the Weight of Five Ounces ; when a fingle Turnep, 

 having no more Scope of Ground, and, in all refpedts 

 (but the Vicinity of the Charlock), equal, weighs 

 Five Pounds, yet that Charlock does not weigh One 

 Pound. 



And where Three Turneps coming up, and grow- 

 ing thus contiguous, will weigh Four Pounds ; a 

 Charlock joined with Two or Three Turneps, all 

 together, will be lefs than one Pound, upon no lefs 

 Space of Ground. 



This Obfervation cannot be made, except where 

 Turneps are drilled in Rows ; and there 'tis eafy to 

 demonftrate, that a Charlock, during the time of its 

 fhort Life, draws much more Earth than a Turnep of 

 equal Bulk, from an equal Quantity of Ground (c). 



The 



(c) 'Tis certain that Turneps, when they ftand for Seed, fuck 



and impoverish the Ground exceedingly : For though they are of 



/ 4 



