Vol. XXII. No. 11.] 



POPTJLAE SOIEITCE NEWS. 



1G3 



Practical C&emtstrp anlJ tijt 3[rta. 



SOAP. 

 The familiar substance soap is, chemically 

 speaking, a true salt, or combination of an 

 acid with a base. The acids which form soap 

 are obtained from fats and oils, and are known 

 as fatty acids. A great variety of animal and 

 vegetable substances are used in soap-making, 

 such as pahn oil, cocoanut oil, olive oil, tallow, 

 lard, and the fat of fishes and other animals. 

 The chemical reaction is the same, however, 

 in all cases. The fatt3- acids, palmitic, stearic, 

 oleic, etc., exist in the fats, combined with 

 glycerine as a base, forming the substances 

 knoivn as palmitine, stearine, or oleine. Tal- 

 low, for instance, is a mixture of stearine, 

 palmitine, and oleine. When these are melted, 

 and toiled with a caustic alkali, such as sodic 

 hydrate, glycerine is set free, and palmilate of 

 soda, or soap, is formed. The reaction ex- 

 pressed bj' symbols is as follows : — 



(UieHaiOjJaCsHs 

 Palmitine. 



+ SNaOII = (C,oH3,()jXa)3 

 Sodic hydrate. Bodio palinitalc. 



Glycerine. 



In the above reaction hard soap is formed : 

 but if potash had been used instead of soda, 

 a jelly-like mass, known as soft soap, would 

 have resulted, containing the glycerine and 

 impurities present in the substances used. 

 Chevreul, the venerable French chemist, now 

 in his one hundred and third year, was the 

 fiist to study and explain this peculiar reaction, 

 commonly known as saponification. 



It is to be noted that the caustic alkalies, or 

 hydrates, must be used in this [iiocess, as the 

 reaction does not occur with the alkaline car- 

 bonates which are more commonly- met with. 

 In wood ashes the alkali occurs as carbonate, 

 and the lye must be treated with quicklime 

 to remove the carbonic acid. Carbonate of 

 soda is often added to soap for the purpose of 

 increasing its cleansing power; but it does 

 not enter into chemical combination, and is 

 an undesirable addition. It is never found in 

 the best soaps. 



Resin is a common constituent of the 

 cheaper grades of soap, and forms a chemical 

 combination with alkalies. It is not a true 

 soap, however, and is of little value, except 

 to the manufacturer by increasing the weight 

 of the product. 



The practical operation of soap-boiling is 

 one requiring considerable skill. The alkali 

 and fats are boiled together for several hours, 

 forming a mass known as soap glue. Common 

 salt is then added, which precipitates the soaj) 

 from the water, glycerine, and impurities. 

 The soap rises to the top of the mother liquor, 

 which is drawn oflT by a tap at the bottom of 

 the kettle. This process is sometimes re- 

 peated, and the hot soap is then ladled out 

 into wooden frames, where it is allowed to 

 harden into a solid cake, which is afterwards 

 cut up into bars of the desired size by means 

 of a wire. Soap, when freshly made, always 

 contains a large amount of water, which greatly 

 increases the weight, besides causing it to dis- 

 solve much more rapidly. For these reasons 

 the manufacturers do not take much pains to 



lessen the percentage of moisture, and it is 

 much more economical to use old soap that has 

 been well dried. 



Castile soap is extensively manufactured in 

 Southern Europe from olive oil. It varies in 

 color from pure white to green. The familiar 

 mottled appearance is caused by mixing cop- 

 peras with it, which is changed to sulphide of 

 iron by the sodic sulphide present in the lye. 



Toilet soap is simply ordinary soap, colored, 

 perfumed, and moulded into fancifully shaped 

 cakes. A poor quality of soap is often used, 

 and its deficiencies masked by the color and 

 odor. A good caslile soap is purer and belter 

 in ever\- respect for toilet use, and the special 

 brands of soap so extensively advertised by 

 certain American manufacturers are, as far as 

 our experience goes, unexceptionable in purity 

 and efficiency. Transijarent soap is made by 

 dissolving ordinary hard soap in alcohol, and 

 allowing it to harden in moulds. It is by this 

 means separated from impurities, and a very 

 good and attractive-looking article results. 

 The alcohol is recovered by distilling and con- 

 densing, and used over again. 



The fatty acids also nnite with lime and 

 other bases, forming insoluble soa|is, mostly of 

 little importance. The lime soap is formed 

 when ordinary soap is dissolved in hard water, 

 containing an excess of that base. Soaps of 

 lead, mercury, and iron are used to a small 

 extent in medicine ; but the onl}' important 

 compounds of this class are those of soda and 

 potash. 



The cause of the cleansing power of soap 

 is even j-et somewhat uncertain. According 

 to Chevreul, the soap is decomposed 1)3- the 

 water, setting free double fat acid salts and 

 alkali. The alkali removes the dirt, which 

 is taken up bj- the fat acid salts, and remains 

 susi)ended in the lather. In some respects this 

 explanation is not quite satisfactory ; but what- 

 ever may be the cause of the peculiar proper- 

 ties of soap, it is so extensively used, and of 

 so much iini)ortance in the daily affairs of life, 

 that the amount consumed bj- a nation ma_v be 

 taken as a measure of its advance in civiliza- 

 tion. 



FAST TIME OX AMERICAN RAILROADS. 



Thk liveliest interest was manifested by railroad 

 men in the recent account of the race between the 

 " Flying Scotchman " and the " West Coast Flier " 

 from London to Edinburgh, in which 400 miles 

 were covered by the winner in 7 hours and 25 min- 

 utes. This was an average of something over 53^ 

 miles an hour. There was a general jogging of 

 memories, and overhauling of the records of fast 

 railroad trains on American lines; and they show 

 that, although the British and French roads 

 admittedly make much better time habittially than 

 is made on any of the American lines, some aston- 

 i-'hing and sustained rates of speed have been at- 

 tained here when special efforts were expended 

 with that end in view. 



The best run on record in this country which can 

 be fairly compared with the English run was made 

 over the West Shore road, from Buffalo to New 

 York, on July 9, 1885, when 426 miles were cov- 

 ered in 7 hours and 27 minutes. Quite a large 

 number of railroad men happened at Buffalo to- 

 gether, en route for New York. It was decided to 



see how quickly they could move overthe new road. 

 At the start the railroad men had their watches 

 out, and soon the mile-posts were flying past every 

 4.3 seconds. That speed was held so steadily, that 

 the greater part of the run was made at the rate 

 of 45 seconds to the mile, or from 70 to 83 miles 

 an hour. From East Buffalo to Genesee Junction, 

 61 miles, took 56 minutes ; from East Buffalo to 

 Newark, 03.4 miles, 97 minutes ; from Alabama 

 to Genesee Junction, 86 3 miles, 30 miimtes. The 

 97 minutes to Newark included stops of 9 minutes, 

 making the actual running time for the 93.4 miles, 

 88 minutes. From Newark to Frankfort, where 

 the conditions for running were not so good as 

 before, the run of 108.3 miles was made in 134 

 minutes, including 17 minutes for stf)ps. From 

 East Buffalo to Frankfort, 2U2 miles, the time was 

 240 minutes, of which 35 minutes were consumed 

 in stops. The journey was timed with the utmost 

 care for the purpose of tabulation. In the table 

 there are niaiked several miles which were made 

 at the speed of 78 miles an hour, one at 84 miles, 

 and the next, between Genesee Junction and Chili, 

 at 87 miles. 



On Oct. 8, 1885, over the same road, a burst 

 of speed was tried for 11 miles betweeu Genesee 

 Junction and East Buffalo, to satisfy Superintend- 

 ent J. E. Liiyng, who was on the train. The run 

 occupied 512 seconds, — an average rate of 74 miles 

 an hour. Three of the miles were made at the 

 rate of 80 miles an hour, one at 77, and one at 75. 



On the New York Central road a newspaper 

 train with two cars, weighing 60 tons, hauled into 

 Syracuse Sunday morning, Aug. 8, 1886, at ten 

 o'clock, an hour late. '1 he train was booked to go 

 from New York to Buffalo in 9^ hours. Orders 

 came to try to make up the time on the further run 

 of 148 7 miles to Buffalo. John W. Cool, one of 

 the best engineers on the road, mounted his cab, 

 bound to obey the order. lie started out at 54^ 

 miles an hour. At the end of the three miles his 

 speed increased to 66 miles an hour, and then to 74 J. 

 lie stopped at Rochester for water, and slowed up 

 after pa.'<sing Crittenden. His average speed from 

 Syracu>e to Rochester was 07 1^ miles per hour, from 

 Rochester to Buffalo 63 72 miles per hour, and 

 from Syracuse to Buffalo 65 6 miles an hour. The 

 run of 148 7 miles was made in 136 minutes. 



Tlie most remarkable long-distance run on 

 record was when the Jarrett-l'almer combination 

 went from New York to San Francisco in half 

 time, or 3^ days. Their train left the Pennsylva- 

 nia Station in Jersey City at 12.53 on the uioru' 

 ing of June 1, 1876. They were not to make a 

 stop until they reached Pittsburgh. An engine and 

 baggage-car, on the approach of the special to 

 Hai risburg, got up a speed of about 50 miles, and 

 pa.s.sed mails to the special by running along an 

 adjoining track for several miles, while the mail- 

 bags were thrown from train to train. The run to 

 Pittsburgh, 438^ miles, took 10 hours and 5 min- 

 utes, — an average of 43^ miles an hour, notwith- 

 standing the Alleghanies. From Pittsburgh to 

 Chicago, 458 3 miles, took 11 hours and 6 minutes, 

 — an average of 42 1 miles, including 25 stops and 

 4 changes of engines. Fiom Chicago to Council 

 Bluffs, 491 miles, took 11^ hours, — an average of 

 42.6 miles, although there was a record for part of 

 this journey of 62 2 miles. Over the Union Pacitic 

 the iHin of 1,032.8 miles from Omaha to Ogden 

 was made in 24 hours and 14 minutes, at an aver- 

 age of 41 miles, and a maximum of 72 miles an 

 hour. • The brakes became worn at Ogden, and 

 hand-brakes had to be used, retarding the onwaid 

 jouiney i,oniewhat. San FrancLsco was safely 

 reached at 12 57 on June 4, and the running time 

 for 3,313^ miles was 84 hours 17 minutes, — an 

 average of 40 miles an hour. — N. Y. 'limes. 



