272 Mr. Gore on Thermo-Electric Properties of Liquids. [Mar. 28, 



to the intra-placental maternal blood- spaces ; the form and structure 

 of the chorionic villi : and to the relation of the maternal blood to the 

 capillaries of the villi. 



The result of this comparison proves that the Macacus and human 

 female closely correspond in the form of the uterus, and in the 

 arrangement of the foetal membranes, and that they both possess a 

 discoid placenta, which in the Macacus is divided into two lobes, but 

 is not so divided in the human placenta. In the arrangement and 

 relative position of the constituent parts of the placenta they also cor- 

 respond ; and although some differences of detail in the characters 

 of some of the structures occur, yet, in the main features of con- 

 struction, makroscopic as well as microscopic, they have a close 

 resemblance to each other. 



V. " On the Thermo-Electric Properties of Liquids." By G. 

 Gore, LL.D., F.R.S. Received March 12, 1878. 



(Abstract.) 



In this communication, the author has described an improved appa- 

 ratus for examining the thermo-electric properties of liquids, by the 

 use of which, with the precautions stated, all sources of error in such 

 experiments appear to be removed ; he has also described a number of 

 experiments he has made with it, and the results obtained. 



By employing a sufficient number and variety of electrically- con- 

 ducting solutions, of acids, salts, and alkalies, in those experiments, he 

 has discovered several exceptions to the usual effect he had formerly 

 obtained, viz., that acid liquids are thermo-electro-positive, and alka- 

 line ones thermo-electro-negative ; and has sketched a diagram repre- 

 senting the thermo-electric behaviour of heated platinum in three of 

 the exceptional liquids. 



Reasoning upon the satisfactory results obtained, he concludes : — 

 1st. That the electric currents are not produced by chemical action ; 

 2nd. Nor by a temporary disassociation of the constituents of the 

 liquid ; 3rd. Nor by the action of gases occluded in the metals ; 

 4th. But that they are produced purely and solely by the heat, and 

 that heat disappears in producing them ; 5th. That they are immediate 

 or direct effects of the heat, and that aqueous conducting liquids, there- 

 fore, possess true thermo-electric properties : 6th. That the current is 

 a result of a difference of thermic action at the surfaces of the two 

 pieces of metal: 7th. That it is a product of a suitable molecular 

 structure of the liquid, a change of such structure resulting from 

 alteration of temperature, and a direct conversion of heat into elec- 

 tricity ; and 8th. That the circumstance which is most influential in 



