Progress of Invention. 319 



are brought out with the greatest sharpness, and the most perfect 

 accuracy. Impregnation in this way can be used for a variety of 

 purposes. After the action of the hydrochloric acid, washing out with 

 water, and drying, the wood may be cut with remarkable facility, 

 and it answers admirably for the purposes of the carver. The 

 drying is effected by forcing air, at a temperature of about 100° 

 Fahr., through the cells. The moisture is thus carried off with 

 great rapidity ; and, as the contraction is uniform through the whole 

 mass, no cracks are produced. Dyes also may be .introduced in the 

 same manner into the entire substance of the wood, or matters cal- 

 culated to preserve it from decay. Soluble glass, or recently pre- 

 cipitated silex, renders it both very durable and thoroughly 

 incombustible. 



New Self-registering Thermometer. — This new maximum 

 thermometer, which is of great simplicity, resembles the ordinary 

 spirit thermometer, except that a small enlargement is blown on the 

 stem, at about one-third of its length from the bulb. In this 

 enlargement is placed a small globule of mercury, which, as long as 

 the spirit continues to ascend in the stem, remains in its place, but 

 when the spirit falls, descends along with it, dividing it into two 

 portions, the upper one of which will continue nearly equal to the 

 greatest distance to which the spirit reached above the enlarge- 

 ment. As that distance is easily measured on a scale, placed for 

 the purpose, the maximum height which the temperature attained 

 during a given interval, is easily found, no matter how low the 

 temperature may have subsequently become. Heating the instru- 

 ment until the globule of mercury reaches the enlargement, and 

 then laying it on its side until it cools, prepares it for a new 

 observation. 



Utilization op South American Beef. — Sixteen years ago 

 Liebig obtained the pure essence of meat, and demonstrated that 

 it contains all the nutritive matter of the animal substance ; but as, 

 on the score of economy, there was no inducement to prepare it, its 

 use has been nearly confined to invalids, to whom it is of the greatest 

 benefit. It is exceedingly nutritious and very digestible, it hastens 

 the recovery of strength in an astonishing way, and may be given 

 in gastric fever and other diseases in which ordinary food cannot 

 be digested. It is so agreeable that after their recovery patients 

 continue to use it with pleasure, which is not the case with pre- 

 parations of gelatine. The latter contain very little nutriment, 

 and they soon become disagreeable to the palate. Eighty per 

 cent, of the extract of meat is nutritive matter, but only four or 

 five per cent, of the gelatine. According to the calculations of 

 Liebig, one pound of the former, with bread, potatoes, and salt, 

 would afford a meal to 128 persons. It may be kept for a very 

 long time : Liebig found some he had prepared fifteen years before, 

 perfectly fresh. In fact, it seems to possess antiseptic properties. 

 A quantity of it, in pots, merely covered with paper, was stored in 

 a damp cellar. Even the inside of the pots became mouldy, but 

 there was no mould whatever on any part of them which was in 

 contact with the extract. The latter is extremely portable, since 

 one pound of it contains the nutritious matter of thirty-two pounds 



