Feb. 17, 1888,] 



SCIENTIFIC NEWS. 



153 



AUTOMATIC TEMPERATURE REGU- 

 LATOR. 



SEVERAL methods exist for keeping rooms or drying 

 chambers at a constant temperature where gas is 

 employed as the heating agent, but recently Messrs. 

 Fischer and Stiehl, of Germany, have invented an 

 apparatus for regulating automatically the temperature 

 of rooms heated by ordinary fires. The principle of this 

 regulator is that the whole of the air required for com- 

 bustion of the fire is made to pass through the apparatus, 

 so that when it is closed, the fire commences to go out. 

 When owing to the fall in temperature, the ventilator is 

 reopened, the fire again becomes brisk. The opening 

 and closing of the air inlet is affected by means of an 

 «lectric current. 



In the room to be heated is placed a thermom.eter, having 



munication with the outside air, the sheet will fall and 

 again close the air passage. 



The alternate opening and closing of the communica- 

 tion is effected by the electro-magnet a. 



THE STRUGGLE FOR EXISTENCE. 



TN his customary clear and incisive style Professor 

 -L Huxley has contributed a most thoughtful and sug- 

 gestive article on the above subject in the February 

 number of the Nineteenth Century. His conclusions 

 too appear to us of an eminently practical nature, and 

 are closely allied with the question of technical educa- 

 tion, now occupying the minds of so many amongst us. 

 Whether our struggles and misfortunes in the world are 

 due to our being in a state of probation, as many sup- 



a platinum wire inserted in the bulb and another in the 

 stem at the temperature desired. The bulb is connected 

 with the regulator, whence a wire runs to a battery, and 

 thence to the platinum wire in the stem. As soon as 

 the mercury in the thermometer rises so as to close the 

 ■circuit the damper is closed, and when the temperature 

 falls the damper is again opened. 



A sectional view of the regulator is given in oui 

 illustration. The damper consists of a sheet of gutta- 

 percha rrr stretched over the opening nn of the air 

 passage p, closing it hermetically. The space enclosed 

 between the plate www, and the gutta-percha sheet is 

 in communication with the chimney by means of the 

 passage m and flue o. As soon as a current of air is 

 established in the chimney, the sheet is raised to the 

 position indicated by the dotted line, and a current of 

 air passes through the holes s and pipe p to the fire. 

 If the communication with the chimney be cut off, and 

 the space above the gutta-percha sheet be placed in com- 



pose, or whether the evolutionist doctrine that they tend 

 to final good, and that " the suffering of the ancestor is 

 paid for by the increased perfection of the progeny," 

 we_ need not discuss in these columns. Firmly as we 

 believe in evolution as a process of natural selec- 

 tion, we think Professor Huxley does well to point at a 

 somewhat popular error of imagining that evolution 

 signifies a constant tendency to perfection. It may just 

 as well be retrogressive as progressive. 



In dealing with some of the more practical questions 

 involved. Professor Huxley points out that in round 

 figures the population of our island is 36,000,000, and 

 that the yearly increase is considerably over 300,000. 

 In other words, " about every hundred seconds a new 

 claimant to the common stock of maintenance presents 

 him or her self among us." The produce of the soil, how- 

 ever, does not provide food enough for half the population, 

 and the other half must be fed with food derived from 

 other countries in exchange for industrial products which 



