TRANSACTIONS OF SECTION B. 653 



The following are some examples of the use of the terms : — 

 Glycerol is a trivoric alcohol. 

 Resorcinol is a divorio phenol. 

 Orthopliosphoric acid is a trivoric acid. 

 Ethyl ether is a divoric base. 

 Mercuric oxide is a divoric base. 

 Ho;0,Hg-(N03)., is divorobasic mercuric nitrate. 

 2HgO,Hfr(NU3)o is tetravorobasic mercuric nitrate. 

 SO3 is a divoric anhydride. 



In the case of bodies of double function such as ZnO, which witli IICl gives 

 ZnCl,,, and with KH0K.^Zn03, it is proposed to use the term amp/iid Thus Al.,0 

 is a hexavoric amphid oxide giving AI^CL and 2A1(0K),. CU.OII is amphid* 

 giving CjII.Cl and C,H,OK. ' " 



Some confusion exists at present in expressing the readiness with which bodies- 

 enter into chemical action. We say, for example, 'strong sulphuric acid is a 

 strong acid,' using strong in the first place to express concentration, in the second 

 to denote chemical eftect. The term avid is suggested as an adjective for general 

 use in this sense. We should thus call KHO a very avid monovoric base. 



With reference to the terms already in use the following proposals are made : 



Monad or monovalent, &c., to be retained for elements and radicals. 



Monatomic, &c., to be retained to denote the total numb?r of atoms in a 

 molecule. 



Acid, to be retained for bodies of acid function. 



Base, to be retained for bodies of basic function. 



Monhydric, &c., to be abolished. 



5. A Sturjy of Ihe Ad 1,711 of Nitric Acid on Benzene. 

 By Professor Lothab Meyek. 



6. On Frofessor Ramsay's MetJiod of determining Specific Volumes. 

 By Professor Lothae Meter. 



7. The Reduction of Nitrates hy Micro-orrjanisms. 

 By R. Waiungton, F.R.S. 



The reduction of nitrates to nitrogen gas in sewage, and waters containing 

 sewage, appears to have been first observed by Angus Smith in 1867 ; he after- 

 wards published many experiments on the subject in the Reports to the Local 

 Government Board of 1882 and 1884. 



The reduction of nitrates to nitrogen in soil was first observed by Schloesing in 

 1873. My own experiments on this branch of the subject were made in 1880. 



That the reduction of nitrates in sewafre is due to the action of micro- 

 organisms was first shown by Meusel in 1875. Beherain and Maquenne in 188-3 

 proved that reduction in soil was brought about by similar agency. 



The conditions of reduction are a medium and temperature suitable for the 

 growth of the organism, the presence of oxidisable organic matter, and the 

 absence of a great excess of air. The products of the reduction of nitrates are 

 either nitrites, nitric oxide, nitrous oxide, or nitrogen gas. The difference in 

 the product is determined partly by the conditions in which tlie organism acts, 

 and partly by the specific character of the organism. Up to the last two years- 

 experiments have been generally made with natural mixtures of ori^'anisms. 

 Working with such mixtures it is easy to conclude that the result depends on the 

 composition and condition of the medium ; such conclusions have to be con- 

 siderably modified when we become acquainted with the results yielded by 

 individual species of bacteria. 



In 1886 Gayon and Dupetit published a splendid research on the reducing 

 powers of certain individual species of bacteria. Reduction to nitrites thev find 



