286 



POPULAR SCIENCE MONTHLY. 



1 



see that mothers are made of the same 

 stuff all over the world, Papuan mam- 

 mas being equal to any of our peasant 

 women or fine ladies in the point of 

 vanity as far as concerns their chil- 

 dren." 



Meat Extracts. — An interesting ac- 

 count of the history and preparation of 

 meat extracts was recently given as a 

 lecture before the Society of Arts (Eng- 

 lish) by Charles R. Valentine. The idea 

 of concentrating the body of an ox into 

 a thimbleful of elixir seems to have been 

 a very old one. Until the work of Jus- 

 tus von Liebig, about fifty years ago, 

 however, little progress of practical 

 value was made toward this end. Lie- 

 big macerated finely divided beef in 

 cold water, or in water not above 150° 

 F. The water dissolved from sixteen to 



twenty-four per cent of the weight of 

 the dry flesh. This infusion was heated, 

 the albumen and red coloring matter of 

 the blood coagulated, and was separated 

 as a flocculent precipitate. The re- 

 maining solution has the aromatic taste 

 and all the properties of soup made by 

 boiling the flesh. The infusion was 

 then evaporated at a gentle heat. The 

 residue amounted to about twelve or 

 thirteen per cent of the original (dry) 

 llesh. This is in rough outline the pro- 

 cess of meat-extract making. This ex- 

 tract is simply an evaporated beef tea, 

 containing the extractive matters of 

 beef, and in virtue of these possesses 

 medicinal and dietetic properties of 

 value. But it is in no sense a substi- 

 tute for beef, as the latter's most impor- 

 tant food constituent — albumen — it does 

 not contain. 



MmOR PARAGRAPHS. 



It appears from tables of Some Sta- 

 tistics of Engineering Education, com- 

 piled by President M. E. Wadsworth, 

 of the Michigan College of Mines, that 

 such education has been, in the United 

 States, on the whole a thing of com- 

 paratively recent date, the oldest school, 

 the Rensselaer Polytechnic Institute, 

 having been established in 1824; the 

 next, the Lawrence and Sheffield 

 Schools, in 1846 and 1847; and the Co- 

 lumbia School in 18G3. Civil engineer- 

 ing has led in this country, and has had 

 various periods of advance, as in 1887- 

 '88, and depression, as in 1896-97. Me- 

 chanical engineering progressed till 

 1886-'87, when the number of students 

 fell off, and the same happened with 

 electrical engineering, " which fiirther 

 suffers a natural reaction from having 

 been greatly overdone." As a rule, 

 most of the schools in the United States 

 seem to run to specialties, one or two 

 of the courses being usually more con- 

 spicuous than the others. 



The importance of some arrange- 

 ment by which vessels may be informed 

 of each other's approach in fog and dark- 

 ness has given rise to many devices; 

 the only one, however, which has as yet 

 proved practical is the fog-horn or siren, 

 and this has many disadvantages. Sev- 

 eral fatal collisions at sea during the 

 past year have given rise to renewed 



interest in the subject, and a number of 

 new methods have been suggested. M, 

 Branley, a French physicist, in a note 

 presented to the French Academy sug- 

 gests that each vessel be provided with 

 a number of extremely sensitive mag- 

 netic receivers, or coherers, and a pow- 

 erful magnetic transmitter. Periodical 

 signals being made with the transmit- 

 ter, corresponding impressions would 

 be made upon the receivers of approach- 

 ing vessels. The principal difliculty 

 with this scheme lies in the fact that 

 the receivers of a vessel will be affected 

 by its own transmitter. Tliere are sev- 

 eral methods by which this difficulty 

 may be overcome, however. Different 

 signals may be employed, or the inter- 

 val between signals may be regularly 

 varied. M. Branley calls attention to 

 the influence of a metallic envelope 

 surrounding a coherer, and shows that 

 when the coherer is thus completely 

 surrounded it is imaffected by the in- 

 fluence of a transmitter. By thus in- 

 closing the receiver on a ship at the 

 instant of the operation of the trans- 

 mitter of the same vessel, the above dif- 

 ficulty might be avoided. 



Wmr.E we can not collect roses from 

 our gardens in January and maple blos- 

 soms from the woods in February, yet, 

 as Prof. W. J. Beal shows in a bulletin 

 of the ^Michigan Agricultural College 



