298 HERMANN VON HELMHOLTZ 



the air, and maintaining it there, by even the most ingenious 

 winged mechanism, if it is to be worked by his own muscular 

 power. If air-balloons and ships are compared on Helmholtz's 

 principle, we obtain the interesting result that if the balloon 

 weigh once and a half as much as the operator whom it carries, 

 the ratio between working force and weight would be the 

 same as in a war-ship. 



At the close of the summer session (1873) Frau von Helm- 

 holtz took the children to their home in Baden, while Helmholtz, 

 overwhelmed with work, spent the month of July in com- 

 parative solitude at Berlin. 



1 Last night I was alone in the house, and was led by Heyse's 

 novel to look up Schopenhauer's Essay on Woman, but only got 

 to the chapter on Love, which I read on the balcony by lamp- 

 light. He is a clever fellow, but has a passion for vulgarity, 

 and turns away from every higher suggestion, even where it is 

 obvious/ 



On August 3 he writes to his wife : 



' I stayed at home, prepared the concluding lectures of my 

 mathematical course, and have at last finished reading Zeller's 

 Kirche und Staat. I must say that the book interested me, 

 although it deals with things that have been overmuch talked 

 about. I had previously seen nothing so reasonable and well 

 grounded on this subject.' 



At the beginning of the holidays he went as usual to 

 Pontresina, and when the never-failing cure of the Engadine 

 had relieved his cardiac trouble, he went on with his wife to see 

 the Exhibition at Vienna, and thence alone for a first visit to 

 Florence, sending his wife enthusiastic descriptions of all that 

 he saw both in Art and Nature. 



' I am enchanted and bewildered by all this completeness and 

 beauty, what we have in Germany are only poor fragments ; 

 here one has the principal works of the Masters in inexhaustible 

 fullness. Fra Angelico is distractingly lovely, in whatever he 

 really executed . . . then in the Accademia there are things of 

 Perugino, which in colour and expression come very near the 

 best Raphaels, marvellous things by one Mariotto Albertinelli, 

 of the same period as Raphael, of whom I never heard, nor 

 saw anything before, profound, full of expression, of the most 

 tender poetry of colour/ 



