CONTENTS. 
92, Short account of Ingenhausz’s 
ideas, as to oil of vitriol being ser- 
viceable to plants. Opinions of others. 
92, 93,94. Carbonic acid disengaged 
by putrefaction, ib. Ingenhausz’s 
account of gypsum, ib. Quantity of 
plaister per acre: and mode of apply- 
ing. 95, 96. Indian corn 96—7. Plais- 
ter must be kept superficial. Its ope- 
ration not perceptible on winter 
grain. 97, 8 Plaister with dung.— 
Lot onwhich it was first strewed, 
98. Manures produce carbonic acid. 
Plaister with animal or vegetable 
manures, most efficacious, 99, 100. 
Mode and cause of operation, and 
repetition, ib. Constant success with 
plaister. Clover with plaister, agrees 
the best of any other grass. Excessive 
operation, exhausts its powers in a 
short time, 101. It is the sulphuric 
acid, which constitutes the operative 
principle of plaister. POSTCRIPT, 102, 
3,4. Dr. Priestly’s opinion of what 
constitutes the food of plants. Obser- 
vations thereon, 105, 6, and opini- 
ons of Ingenhausz and Chaptal, ib. 
English account of gypsum, 108, 9, 
10. Observations thereon, 111, 12, 
13, 14. Success of Mr. Smythe, m 
England. Extract of a letter from 
Robert Barclay Esq. of England.— 
Proposition of experiment to banish 
the Hessian fly ; by means of plais- 
ter, or oil of vitriol, 116, 117. Com- 
