Proceedings of the Polytechnic Association. 781 



The latest advices from Hawaii state tliat the island is still shaking 

 and quivering, making forty-one days of earthquakes. Nothing new 

 as yet regarding lava flows, although the inhabitants feel coniident 

 another flow must take place before quiet will be restored. 



Adjourned. 



September 17, 1868. 



Professor S. D. Tillmax in the Chair ; Mr. C. E. Emery, Secrctaiy. 

 iS^Ew Peteolp:dm Lamp. 



Mr. Eugg, of Sing Sing, N. Y., exhibited a petroleum lamp burner, 

 in which a perforated plate on each side of the wick separates the 

 air and causes the flame to burn some distance above the metal tube, 

 and so the metal part of the glass chimney is not heated in the least ; 

 an even and free current of air is kept up all the while, and the air 

 being diffused in small streams, the flame is not flickering, but very 

 steady. 



Dr. J. B. Rich remarked that the steadiness and brilliancy of the 

 flame of this lamp made it preferable to daylight for microscopic 

 purposes. 



Xew Mode of Pbeserving "Wood. 



Mr. Franklin presented a number of specimens of wood impreg- 

 nated with resin under pressure. The inferior woods, he said, such 

 as hemlock, pine, oak, chestnut, birch, maple, ash, spruce, hickory, 

 etc., are by this process transformed into costly and valuable ones, 

 resembling rosewood, black walnut, ebony, mahogany, etc. The rapid 

 destruction of our forests, owing to the increasing demand of manu- 

 factures, railroads, and the short-sighted policy of settlers in clearing 

 off" their laud, with little or no reference to the future, has for some 

 time attracted public attention to the necessity of providing against 

 the diminution of the supply of wood. Economists foresee the time 

 when our once densely wooded hills and plains will become as barren 

 as those of Greece, if the consumption of wood goes on at the present 

 rate, and no means are taken to make up the loss. 



There are two ways in which this can be done. The forests can 

 either be replenished, as is done in some parts of Europe, or the wood 

 used for railroad ties, buildings, dock piles, etc., may be rendered 

 indestructible, and thereby lessen the demand upon the forests. This 

 plan has often been attempted, with varying success. The latest in 



