June 30, 1893.] 



SCIENCE. 



357 



It is especially urged tbat all chemists who intend visiting the 

 World's Fair take this occasion to do so, by which they can com- 

 bine the pleasure of visiting the Exposition with the benefit de- 

 rived from attendance at the congress. To American chemists an 

 especial appeal is made to be present for the purpose of welcoming 

 our foreign visitors and showing them the progress of chemical 

 science in the United States. Harvey W. Wiley. 



THE EFFECT OF FOOD UPON THE COMPOSITION OF BUT- 

 TER. 



BY FRED W. MORSE, DURHAM, NEW HAMPSHIRE. 



Practical dairymen, who produce a high grade of butter, lay 

 great stress upon the quality of food with which their cows are 

 fed. Chemists, who have had much to do in the examination 

 of butter for adulterants, have observed that the samples from 

 one region have steadily varied in their composition from those 

 of another region, where different practice prevailed in feeding. 

 These facts have led to many experiments, both in Europe and 

 America, to find out the specific action of different foods upon 

 the composition of butter. 



This product of the dairy is composed of fat, water, salt and 

 curd ; and of these, the cow is responsible for only the fat and 

 the curd. The former constitutes about eighty- five per cent 

 and the latter barely one per cent of the butter, therefore chem- 

 ical examinations for variations due to food have been confined 

 wholly to the fat. Butter-fat differs from the fat deposited in 

 the body of the animal by having from five to seven per cent 

 of volatile fatty acids, and only eighty-seven to ninety per cent 

 of insoluble, fatty acids, while tallow has ninety-five per cent of 

 the latter and less than one-half of one per cent of the former. 

 The volatile acids give butter fat its characteristic flavor, and 

 also cause it to be softer than tallow. Butter fat also differs 

 from tallow in having less oleic acid among its insoluble acids. 

 These two characteristics of butter-fat have been studied more 

 than any of its other properties, because of their relations to 

 adulteration?, and the studies of food effects have so far been 

 confined to the same lines. 



In the course of investigations, it has been found that in gener- 

 al, the widest variations in volatile acids and oleic acid are due 

 to the progress of lactation, the latter increases and the former 

 decrease as the period advances. Individual cows also vary 

 widely from one another in the composition of their butter fat, 

 but with regard to the breeds, no definite conclusions can be 

 made. 



The effect of food is greater upon the oleic acid than upon the 

 volatile acids and, in nearly all cases, variations in this constitu- 

 ent of the fat have been closely related to variations in the firm- 

 ness of the butter. This is to be expected, as oleic acid is an oily 

 liquid at summer temperature, and the butter is softer or harder 

 as this acid is present in greater or less amount. 



Many of the foods have been tried in such liiiiited amounts 

 that it is unsafe to draw conclusions, therefore only such foods 

 will be mentioned here as have been used in repeated trials. The 

 most notable effect has been produced by cotton-seed and cotton- 

 seed cake. Whenever it has been fed, the volatile acids and oleic 

 acid have been depressed below the average ; the butter is defi- 

 cient in flavor and often too hard to be easily cut with a knife. 



In strong contrast to this action of cotton-seed, is the effect of 

 gluten-meal, a by-product from the manufacture of corn-starch. 

 This food is especially effective in raising the oleic acid above the 

 average, and also produces a butter-fat high in volatile acids. 

 The butter from this food is frequently too soft for an ideal 

 product. Corn-meal, however, has always produced a butter-fat 

 low in oleic acid, but has shown no action on the volatile acids. 

 Clover, dry or green, has produced fat high in volatile acids, and 

 with oleic acid slightly above the average. The same is also true of 

 spring pasturage. Early cut straw generally produces a fat with 

 volatile acids and oleic acid below the average. 



The action of clover and pasturage in increasing the volatile 

 acids, and that of corn in lowering the oleic acid, explains the 

 practice of the makers of first-class butter, who rely upon these 

 foods to produce a good flavor and firm grain. 



ELECTRICAL NOTES. 



The present Electrical Exhibit at the World's Fair contains 

 much more that is of interest from an engineering standpoint than 

 from a purely scientific one. Magnificent as the engineering dis- 

 play is, there is little that is new. Everything is now thoroughly 

 mechanical, one no longer sees the monuments of tortured inge- 

 nuity which used to pervade the former exhibitions; in its place 

 are the results of sound and competent engineering skill. 



The multipolar machine has evidently come to stay. Three 

 years ago there was not, I believe, a single large multipolar ma- 

 chine made. Almost the only makers of machines above 100 

 horse-power were the Edison, Brush, and Westinghouse Compa- 

 nies (we are speaking of America, of course; on the Continent of 

 Europe multipolar machines have been the rule), and their ma- 

 chmes were all bipolar. Now there is on exhibit hardly a single 

 machine above 50 horse-power which is not multipolar. Splendid 

 examples of these are the Westinghouse, Thomson-Houston, and 

 Edison direct connected generators. 



The general use of the toothed armature is also a new feature. 

 A short time ago the hardy individual who should have proposed 

 designing a large dynamo with toothed armature would have been 

 told that it was impossible to do it, that the consequent increase 

 of self-induction would make it spark so badly that it could not 

 be run, that the only way to make a dynamo whose brushes 

 would not need shifting between full and no load was to have a 

 big air-gap, and all this would have been backed up by alarming 

 mathematical quotations from Ayrton and other writers. 



Now we see that the impossible way is the only way, and the 

 designer who neglects the aid of the toothed armature is handi- 

 capping himself very much. In passing, one may notice that, if 

 one may judge from several recently-read papers in the English 

 Institute of Electrical Engineers, European designers are not 

 able as yet to design a toothed armature which shall not spark, 

 shall require no shifting of brushes, and shall be highly eflicient. 

 Even the machines, which probably furnished the encouragement 

 to American designers to try the toothed armature, i.e., the Brown 

 machines for electro-metallurgy, we learn, recently, had to be sent 

 back to the factory, the armature turned down, and rewound 

 with an exterior winding. 



Among the new things in engineering, the large two-phase 

 1,000 horse-power generators of the Westinghouse Company de- 

 serve especial attention. The large amount of work now being 

 done in this line by the various companies is a good augury for 

 the rapid development of the system. If this proves a success, 

 the days of the continuous current will be ended, so far as engi- 

 neering is concerned. There are three things so far which ha^e 

 hampered the alternating current : (1) Poor all-day efficiency of 

 transformers, (2) noisy arc-lights, and (3) absence of motors. The 

 recent developments in transformer design have resulted in trans- 

 formers with an all-day efficiency of 94 per cent; the new low- 

 potential arc-lamps give abetter light than the continuous-current 

 lamps, and as noiseless; and there only remains the development 

 of the motor system, which now seems to be within sight. 



Electric welding is evidently no longer a thing of the future. 

 There are a number of firms making displays, who are using the 

 Thomson process in their business. Several of the wagon-making 

 firms use the welders to make tires and weld axles; wire-making 

 companies use them to join lengths of wire; they are used in 

 making shells for modern machine and quick-firing guns; for 

 joining up lengths of pipe in ammonia ice-machines; and for weld- 

 ing rails together to form a continuous track. This last is a most 

 interesting exhibit, as, if successful in practice, it will lead to a 

 new method of railway construction, for street railways at least. 

 A track has been in operation for some time near the Thomson- 

 Houston factory in Lynn, and the results seem to have been very 

 good. No trouble was experience from expansion or contraction, 

 the friction of the rails in the ground preventing displacement 

 and creeping, and the expansion merely manifesting itself as a 

 stress in the rails, well within the elastic limit. 



Among recent practical applications of electricity are the electric 

 chimes and tower-clock system, now on exhibition in the tower in 

 the centre of the Manufactures and Liberal Arts Building. These 

 are the invention of Mr. Attwood. and the chimes have been used for 



