r^S6 TRANSACTIONS OP THE AMERICAN INSTITUTE. 



wonderful than the writing telegraph of Morse, In House's arrangement 

 electricity is only used to produce a correspondence of motion in the ma- 

 chinery at the different ends of the line. The type wheel, having on its 

 periphery the twenty-six letters of the alphabet in capitals, and a period 

 and hyphen, making twenty-eight characters, is revolved by twenty-eight 

 teeth, the propelling power at each end of the line being a spring or weight, 

 wound up by clock work. The wheel can only move the distance of one 

 tooth when the circuit of electricity is broken or closed, consequently by 

 breaking and closing the circuit fourteen times, the wheel would make one 

 revolution. This is done very rapidly by means of condensed air, which 

 gives to a rod a vibratory motion of only one-sixty-fourth of an inch. When 

 the type wheel stops an eccentric brings down upon the letter exposed, al- 

 ready inked, the paper strip which receives the impression and moves for- 

 ward one step, to be ready for another. The operator is placed before a 

 key-board, having twenty-eight keys, or one for each character or letter. 

 On this he spells the word, by pressing each key corresponding with the 

 letters in it; as the type wheels revolve at the same speed, the spelling at 

 one end and the printing at the other follows each movement. Other tele- 

 graphs have been invented. Mr, Morse is also the inventor of a chemical 

 telegraph. Mr. Hughes is said to have expedited the action of the printing 

 telegraph. These improvements were all made in this country, and it may 

 be gratifying to some to know that just before the breaking out of the re- 

 bellion, the United States contained more miles of telegraphic lines than 

 all the other countries combined. 



Meteorology was the subject selected for the next discussion. 



Adjourned. 



American Institute Polytechnic Association, 1 

 January 14, 1864. ) 



Chairman, S. D. Tillman, Esq.; Secretary', Mr. B. Garvey, 

 The Chairman commenced the miscellaneous business by reading the fol- 

 lowing interesting summary of scientific news: 



Essential Oils. 

 ■ J, H. Gladstone, F. R. S., read before the London Chemical Society, 

 December 3d, an interesting description of forty-seven different kinds of 

 essential oils. From the tables of measurements presented by him the fol- 

 lowing facts are derived. The crude oils do not vary essentially in specific 

 gravity, the majority being about 0.9 at 15.5° Centigrade, Peuang Pat- 

 chouli, Penang Citronella, Myrtle and Cassia were all slightly heavier than 

 water. The density of the oil of wintergreen was 1.1423. Their action 

 on light was found 1^ be more refractive and dispersive than that of the 

 lighter oils; the least action being from Bergamot and Cajeput, The differ- 

 ence in circular polarization was marked, no great dependence, iiowever, is 

 placed upon this characteristic, as samples of the same oils both crude and 

 refined show wide differences. Most of the oils yielded hydro-carbons of 

 the turpentine type C20 H16. The oil of Birch bark, which gives the pecu" 



